[Senate Hearing 116-252]
[From the U.S. Government Publishing Office]


                                                        S. Hrg. 116-252

 MARIJUANA AND AMERICA'S HEALTH: QUESTIONS AND ISSUES FOR POLICY MAKERS

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                                HEARING

                               BEFORE THE
                               
            SENATE CAUCUS ON INTERNATIONAL NARCOTICS CONTROL
                          UNITED STATES SENATE

                     ONE HUNDRED SIXTEENTH CONGRESS

                             FIRST SESSION

                               __________

                            OCTOBER 23, 2019

                               __________

  Printed for the use of the Senate Caucus on International Narcotics 
                                Control
                                
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                     Available via: www.govinfo.gov
            Senate Caucus on International Narcotics Control          
                              
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                    U.S. GOVERNMENT PUBLISHING OFFICE                    
41-181 PDF                  WASHINGTON : 2021                     
          
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                           JOHN CORNYN, Texas
                      DIANNE FEINSTEIN, California
                          JACKY ROSEN, Nevada
                            
                            
                            C O N T E N T S

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                                                                   Page
Panel I Consisting of:
Jerome Adams, MD, Surgeon General of the United States, 
  Department of Health and Human Services, Washington, DC........     4
Nora Volkow, Ph.D., Director, National Institute of Drug Abuse, 
  North Bethesda, MD.............................................     5

Panel II Consisting of:
Robert Fitzgerald, Ph.D., Professor of Pathology, University of 
  California-San Diego, San Diego, CA............................    17
Staci Gruber, Ph.D., Professor of Psychiatry, Harvard Medical 
  School, Boston, MD.............................................    19
Sean Hennessy, Pharm.D, Ph.D., Professor of Epidemiology, 
  University of Pennsylvania Perelman School of Medicine, 
  Philadelphia, PA...............................................    21
Madeline Meier, Ph.D., Assistant Professor of Psychology, Arizona 
  State University, Tempe, AZ....................................    22

 
 MARIJUANA AND AMERICA'S HEALTH: QUESTIONS AND ISSUES FOR POLICY MAKERS
                  CAUCUS ON INTERNATIONAL NARCOTICS CONTROL
                              ----------                              


                      WEDNESDAY, OCTOBER 23, 2019

                                       U.S. Senate,
                                                    Washington, DC.
    The hearing was convened, pursuant to notice, at 3:22 p.m., 
in 215 Dirksen Senate Office Building. Senator John Cornyn, 
Chairman, presiding.
    Members Present: Senator Dianne Feinstein, Co-Chairman and 
Senator Jacky Rosen.
    The Chairman. Good afternoon. I would first like to begin 
this hearing by thanking our witnesses, and thanks to my Co-
Chair, Senator Feinstein. We have been looking for a forum to 
have a hearing like this. As in so many areas, it seems like we 
are putting the cart ahead of the horse, and we would now 
really like to hear from the experts about what they can tell 
us about the public health consequences of marijuana use in the 
country.
    So far this year we have centered our efforts on prevention 
of addictive substances from entering the country and 
infiltrating our communities, but now we want to talk about 
something a little different.
    As you know, a 2018 Report by the Substance Abuse and 
Mental Health Services Administration found that an estimated 
43.5 million Americans used marijuana in the last year. The 
percentage of the population 12 years of age and older 
currently using marijuana has increased in recent years from 
under 7 percent in 2010 to more than 10 percent in 2018.
    And while marijuana is still a prohibited drug under 
federal law, more than 90 percent of the states allow for some 
medical use of marijuana in some capacity, and 10 states and 
the District of Columbia now allow for the recreational use of 
marijuana.
    Despite growing acceptance and accessibility of this drug 
and its derivatives, I believe we lack definitive evidence on 
the short- and long-term health implications of marijuana use. 
That is especially true for vulnerable populations like 
adolescents, pregnant women, and people suffering from mental 
health issues.
    Earlier this year, our Surgeon General, one of our 
witnesses here today, issued an Advisory that highlighted the 
risks of marijuana use for pregnant and nursing women and 
adolescents.
    I remain concerned about the lack of evidence regarding 
health risks of these groups, as well as the general 
population. And it may be helpful at some point for the 
witnesses to discuss what type of evidence that the medical 
community considers conclusive, or at least solid enough to 
make a policy determination on. Because there seems to be a lot 
of folk myths and other idiosyncratic ideas that really have 
not gone through the sort of peer review and published 
requirements that most scientific evidence has to go through in 
order to be accepted by policymakers.
    In 2017, the National Academy of Sciences, Engineering, and 
Medicine published one of the most comprehensive studies on the 
research of the health effects of recreational and therapeutic 
use of marijuana and cannabis-derived products.
    It included nearly a hundred conclusions. They found 
conclusive or substantial evidence that cannabis or 
cannabanoids, but not necessarily marijuana or marijuana-
derived cannabanoids, are an effective treatment for chronic 
pain, chemotherapy-induced nausea and vomiting. However, they 
found insufficient or no evidence regarding potential 
therapeutic effects of cannabis or cannabanoids for a variety 
of health conditions considered.
    Additionally, they found substantial evidence that 
marijuana use had increased the risk of motor vehicle crashes, 
the development of schizophrenia, and other psychoses, and 
complications in pregnancy like lower birth weight.
    It is critical for people like Senator Feinstein and I and 
other policymakers to understand the public safety implications 
of increased marijuana use before we dive into the admittedly 
complex and difficult job of changing federal policy.
    In 2018, the Food and Drug Administration approved the 
first drug with an active ingredient derived from marijuana to 
treat rare, severe forms of epilepsy. It was only after 
rigorous studies and a thorough review by the FDA that 
physicians can have confidence in the safety, efficacy, and 
consistency of that drug. All this is to say that there are so 
many questions that still need to be answered.
    Surgeon General, Dr. Volkow, and the experts on our second 
panel will help shed light on what science tells us about the 
public health risks of marijuana and what we still need to 
learn.
    I look forward to hearing the testimony and discussing how 
we can work to prevent youth access to marijuana, and properly 
evaluate the safety and efficacy of any therapies that may 
utilize marijuana and cannabinoids.
    Let me now turn the floor over to my Co-Chairman, Senator 
Feinstein, for any opening remarks she would care to make.
    Co-Chairman Feinstein. Thanks very much, Mr. Chairman. As 
you know, I enjoy very much working with you, so this is a 
pleasure.
    The point of today's hearing is to better understand 
marijuana's impact on public health, and so I thank you very 
much for holding it.
    One thing I have learned is that marijuana is much more 
complex than I thought. It apparently contains hundreds of 
different compounds, all of which produce different effects. I 
am told that much of what we know about marijuana is anecdotal, 
which of course is problematic for us in terms of making 
policy. It is problematic for medical professionals in knowing 
how to treat it. And it is problematic for consumers when they 
use it.
    I am told this is due in part to the fact that marijuana's 
status as a Schedule One Drug makes it difficult to research. 
It is my belief that science should inform our policy, and that 
is why I, along with Senator Grassley and others, introduced 
the Cannabidiol and Marijuana Research Expansion Act which 
would remove barriers to research.
    The NIH recently increased the number of grants awarded to 
study marijuana, and I hope it will continue to do so. This 
will enable marijuana's potential therapeutic benefits really 
to be more understood as they are explored.
    It is important that we learn more about appropriate dosing 
and delivery mechanisms. It is important that we learn how 
marijuana components interact with other medications, how long-
term use impacts the body. It is my understanding that the 
limited existing research has found varying degrees of evidence 
that components of marijuana may effectively treat conditions 
like intractable epilepsy, chemotherapy-induced nausea. I know 
that for a fact from family issues. And, vomiting. Muscle 
spasticity, chronic pain, and short-term sleep disturbances.
    The Food and Drug Administration has approved four 
marijuana-derived drugs to treat many of these illnesses. 
Despite the potential benefits, it is equally important to 
understand its adverse effects.
    For instance, studies show that marijuana can have a 
negative impact on the developing brain--this is one thing I 
hope to hear a little more about--including decreased cognitive 
abilities, loss of IQ, and increased risk of psychosis.
    I am going to end here, Mr. Chairman, in the interests of 
seeing--of listening to our panel, and I will put my remarks in 
the record. Thank you.
    The Chairman. Thank you, Senator.
    Our first witness is Vice Admiral Jerome Adams who serves 
as the 20th Surgeon General of the United States. During his 
tenure as Surgeon General, Dr. Adams has created several 
initiatives to tackle our Nation's most pressing health issues, 
including the opioid epidemic, oral health and the links 
between community health and both economic prosperity and 
national security.
    The Surgeon General issued an Advisory in August of this 
year on the potential health effects of marijuana use for 
adolescent brain development and use by pregnant mothers.
    Our second witness on the first panel is Dr. Nora Volkow, 
who has served as Director of the National Institute of Drug 
Abuse, or NIDA, since May 2003. That is quite a run. As a 
research psychiatrist and scientist, Dr. Volkow pioneered the 
use of brain imaging to investigate the toxic effects and 
addictive properties of abusable drugs.
    If I could ask each of you to limit your opening statement 
to about five minutes, and then we will make your complete 
statement part of the record, and then we can engage in some 
questions and answers, that would be great.
    So let me turn to you, Dr. Adams, to start, please.

STATEMENT OF JEROME ADAMS, M.D., SURGEON GENERAL OF THE UNITED 
                             STATES

    Dr. Adams. Thank you very much, Chairman Cornyn, Co-
Chairwoman Feinstein, and members of the Caucus. I appreciate 
the opportunity to share my recent marijuana advisory with you 
and to join national experts to discuss a complex issue that I 
feel demands our attention and our action.
    As you mentioned, in August 2019 I issued a Surgeon 
General's Advisory on Marijuana Use in the Developing Brain, 
emphasizing the importance of protecting our Nation from the 
health risks of marijuana use in adolescence and during 
pregnancy.
    I did this in response to alarming rates of marijuana use 
among pregnant women and young people, widespread and growing 
access to increasingly potent marijuana through legalization at 
the state level, and mounting evidence that marijuana use poses 
a risk to healthy brain development and to public health.
    As Surgeon General I have visited with communities and 
clinicians in places like California and Colorado, Georgia and 
Texas, Nevada and Oklahoma. And as a former state health 
commissioner myself, I have spoken with health department 
leaders across the country, my friends, many of them reluctant 
overseers of an enormous and poorly informed national public 
health experiment.
    Over and over I hear great and escalating concern about the 
rapid normalization of marijuana use, and the impact that a 
false perception of its safety is having on our communities, 
and specifically our young people and our moms-to-be.
    As you mentioned, sir, as of today 33 states and the 
District of Columbia have legalized marijuana in some way. I 
will say it again: We are conducting a massive public health 
experiment on our citizenry. And with greater legalization, 
young people are reporting a decline in perceived harmfulness 
of the drug. In 2018, only a third of adolescents said they 
thought weekly marijuana use was harmful.
    Marijuana is now the third most commonly used elicit 
substance in adolescents, behind alcohol and e-cigarettes. Last 
year, over 9 million 12- to 25-year-olds reported marijuana 
use, and each day 3,700 adolescents become new marijuana users.
    Unfortunately, the scary truth is that while the perceived 
harm of marijuana is decreasing, the potential for harm is 
actually increasing due to widespread access, increased 
potency, and multiple forms.
    Marijuana is now everywhere, especially in states that have 
legalized. And it can be smoked, drunk, eaten, and baked. As I 
like to say, this ain't your mama's marijuana. Not enough 
people know that today's marijuana is far more potent than in 
days passed. The amount of THC has increased three-fold in 
commonly cultivated plants over the last few decades, and 
dispensary products are often much stronger. Edible oils and 
waxes can deliver unpredictable concentrations of THC often of 
70 percent or more. This is important because the higher the 
THC concentration, the higher the risk to our young people.
    Across the country we have seen increased emergency 
department visits for psychosis and for nonfatal overdose. The 
earlier and more often a person uses marijuana, especially at 
these higher THC levels, the greater the peril.
    Nearly one in five people who begin marijuana usage during 
adolescence will become addicted. Yes, you can become addicted 
to marijuana.
    Science tells us frequent marijuana usage during 
adolescence can impair a child's attention, memory, and 
decisionmaking, and young people who regularly use marijuana 
are more likely to show a decline in IQ in school performance, 
are more likely to drop out, and are even more likely to 
attempt suicide.
    In pregnant women, marijuana is actually the most commonly 
used elicit substance. Between 2002 and 2017, marijuana use 
among pregnant women doubled. Marijuana usage during pregnancy 
can not only affect the baby's brain, but also can result in 
lower birth weight, a marker for early death and disability. 
And that is why that is so important.
    The Colorado PRAM study revealed a 50 percent increase in 
low birth weight in marijuana-using moms. THC is transmitted 
via breast milk, meaning the risk continues even after 
delivery.
    And finally, marijuana and tobacco smoke share some of the 
same harmful components, so no one should smoke either product 
around the baby.
    We already know a lot about the harms and potential harms 
of marijuana use on the developing brain, but I will be the 
first to admit we need to know more. We need to better 
understand the long-term health consequences of prenatal and 
youth exposure to marijuana, as well as strategies to decrease 
harms.
    But I want you to hear me say this: We know enough now to 
deliver sound guidance to protect the future of our Nation's 
youth. My Advisory includes resources to help parents, 
teachers, clinicians, and others safeguard our youth from harm, 
but it will take all of us using the best evidence and 
communicating it clearly to ensure a healthy future for our 
young people.
    This Advisory was carefully written based on the best 
currently available science, with input from NIDA, SAMPHSA, 
CDC, FDA, ACOG, AAP, and others. So please go to 
surgeongeneral.gov and share it.
    I will finish by saying my bottom line to you today is 
this: No amount of marijuana use during pregnancy or 
adolescence is known to be safe. Therefore, communities must 
consider and should not minimize the short- and long-term 
public health impacts of marijuana use.
    Thank you again for the opportunity to share this important 
information, and for your support in promoting healthy fetal 
and adolescent development to protect the youth of America. And 
I look forward to your questions.
    The Chairman. Thank you, Doctor. Dr. Volkow.

 STATEMENT OF NORA VOLKOW, Ph.D., DIRECTOR, NATIONAL INSTITUTE 
            OF DRUG ABUSE, NORTH BETHESDA, MARYLAND

    Dr. Volkow. Good afternoon. Thanks very much for having me 
here, Chairman Cornyn and Co-Chairman Feinstein, and for 
holding this hearing on marijuana.
    It is an opportunity for us to bring to you what we are 
funding at the National Institute on Drug Abuse and what type 
of research we are funding to try to clarify the effects of 
marijuana in the young brain.
    As you mentioned, in 2018 there were 43.5 million people 
who reported use of marijuana in the past year, making it the 
most commonly used illicit drug in the United States, and its 
use is increasing.
    Marijuana exerts its effects by activating cannabinoid 
receptors which are part of our endogenous cannabinoid system 
that modulates multiple physiological processes in our brains 
and bodies. This system emerges early in gestation when it 
plays a critical role in helping to orchestrate brain 
development, which is why exposure to marijuana during early 
development can impact the function of the brain later in life.
    THC, the component of marijuana responsible for its 
intoxicating and addictive effects, freely crosses the 
placenta. Fetal exposure is associated with significant 
negative outcomes, including fetal growth restriction, lower 
birth weight, and preterm delivery.
    Research is ongoing to clarify the mechanisms through which 
it contributes to these effects, and to investigate the effects 
of marijuana to the fetal brain when used by itself or when 
combined with teratogenic drugs such as alcohol and nicotine.
    Adolescents, whose brains are also undergoing major 
developmental changes, are also particularly vulnerable to the 
negative effects of marijuana. Clinical studies of THC exposure 
during adolescence have shown greater sequence sensitivity to 
the rewarding effects of other drugs, which could be one reason 
why dosages of marijuana at a young age are more vulnerable to 
addiction later in life, not just to marijuana but to also to 
other drugs.
    Epidemiological studies have found repeatedly that kids who 
regularly consume marijuana have lower academic achievements 
and a higher risk of dropping out school. Brain imaging studies 
have shown that frequent marijuana use during adolescents is 
associated with structural and functional changes in areas of 
the brain necessary for attention, memory, emotions, and 
motivation, which might account for the adverse cognitive and 
behavioral effects associated with youth marijuana use.
    The association between marijuana use and mental illness is 
another area of major concern, particularly in light of the 
higher content of THC in today's marijuana. Serious mental 
illnesses and suicide are on the rise in our country. And while 
multiple factors are likely contributing to this rise, it is 
imperative to understand if exposure to high potency cannabis 
in adolescence is one of them.
    High potency marijuana can trigger acute psychotic 
episodes, which is one of the main causes for emergency 
department visits associated with cannabis use, which are also 
rising.
    While most of these episodes are short lasting, they can 
become chronic. Multiple studies, though not all, have 
associated adolescent marijuana use with an overall risk for 
the early onset of chronic psychosis such as schizophrenia.
    Adolescent marijuana use is also associated with increased 
risk of suicidal behavior. Many of the studies done to assess 
the effects of adolescent marijuana use have been criticized 
because of certain limitations. For example, some of them may 
have not controlled for other factors that affect adolescent 
brain development. Some may have had insufficient sample sizes. 
Most of them were conducted at the time when THC content in 
marijuana was much lower.
    To address this shortcoming, NIDA is leading two major 
studies. Study one is the Adolescent Brain Cognitive 
Development, or ABCD study, which is the largest long-term 
study of brain development in child health in the United 
States. The study has recruited over 11,000 children, aged 9 to 
10, who will be followed into early adulthood to investigate 
how the brain develops, and how its development is affected by 
substance use, including marijuana.
    The other one, which complements the ABCD study, is A 
Healthy Brain Child Development, or HBCD study, which is part 
of the NIH initiative and is currently in its pilot phase. This 
study would establish a large cohort of pregnant women and 
their infants to assess the child's brain cognitive and 
emotional development longitudinally over the course of the 
first 10 years of their lives. Findings will help researchers 
develop standards for normal brain development in childhood and 
to characterize the long-term impact of prenatal and postnatal 
drug exposures.
    Ensuring normal brain development is fundamental for 
achieving a person's full potential, which is why we owe it to 
the future generations to protect them from the potentially 
disruptive effects of cannabids to their brains and well being.
    Thank you very much, and I look forward to your questions.
    The Chairman. Thank you very much, both of you.
    I am struck, Dr. Adams, by your description as a poorly 
informed national health experiment with regard to marijuana. 
And of course part of what we are trying to do today is have a 
better informed discussion about this national health 
experiment.
    I see some parallels, perhaps--and I would be interested in 
your commentary on this--to what we learned about tobacco 
decades in the past. I even went back, with my staff's help, 
and found some advertisements by the tobacco industry where 
they would tout the health benefits of smoking. And not only 
were those not proven using the sort of peer-reviewed evidence, 
scholarship that we would expect, but there was not disclosure 
of the negative, the detriment to health--things like addiction 
to nicotine, lung cancer, cardiovascular disease, and the like.
    And I feel like there are some parallels, perhaps, here in 
the way we are wading into this debate. Do you think that is 
analogous, Dr. Adams, and Dr. Volkow? Or is it different?
    Dr. Adams. Well, sir, thank you for saying that. Because as 
the Surgeon General, I want every policy decision to have as 
much science infused into it as possible. And you are correct.
    We have seen this play before. We have seen it with a 
number of substances. Once upon a time, cocaine was thought to 
be an effective medicine and harmless. Once upon a time, 
opioids were thought to be good for whatever ails you, and to 
not have any harmful effects and no higher dosage limit.
    And not that I am in any way, shape, or form comparing 
marijuana to those substances, but from a policy point of view 
I think the lesson we should have learned was that we have to 
make sure the science is leading the policy, and that the tail 
is not wagging the dog. And many of the indications that people 
are using marijuana for are unproven. We are overstating the 
benefits and, in my opinion, we are downplaying the risks. And 
that is why I put out my Advisory, because one risk we cannot 
afford to ignore is the risk to our pregnant women and our 
young people, our Nation's future.
    The Chairman. Dr. Volkow.
    Dr. Volkow. Yes, I will completely agree, and I do want to 
state also the other aspect that we are learning with the use 
of marijuana at very high content, is we are finding out 
medical negative effects that we did not know existed. For 
example, a perfect example is the iferamesic syndrome where 
people that take high content THC chronically develop a 
syndrome where they cannot stop vomiting, with very, very 
intense abdominal pain.
    This was not described until 2006. And again, we have never 
seen it because we did not get exposed to this type of 
marijuana. So my concern relates to the fact that if we are not 
looking at something, particularly as we for example are 
discussing the use of marijuana in pregnancy, if we do not 
evaluate the outcome in these infants, we will not be able to 
understand what could be potentially very negative effects.
    And that is illustrated also with tobacco. In nicotine we 
did not know that smoking during pregnancy could have such 
negative effects until we studied it.
    Dr. Adams. And I am so glad you have someone on the second 
panel who is an expert on MVAs. There is this big misbelief out 
there that marijuana makes you a better driver, but the 
Colorado data shows us that MVAs went up, fatal MVAs went up in 
Colorado involving marijuana usage.
    And again going back to young people, I have got a teenager 
who is about to drive. The chips are already stacked against 
him. And we know that, just statistically speaking. The last 
thing we want is for these young people to think that marijuana 
use is safe or, Heaven forbid, that it actually will make them 
a better and more relaxed driver and lose even more of our 
teenagers on the roads now than what we already are.
    The Chairman. I know much of your testimony so far has 
focused on adolescents, pregnant women, and people with other 
conditions that would maybe make them more vulnerable, but are 
you suggesting, by inference, that marijuana consumption for a 
consenting adult who is otherwise healthy is harm-free?
    Dr. Adams. Well, as Surgeon General of the United States, 
the first thing I would say is absolutely not. There are plenty 
of substances out there which adults can partake of that are 
not only not harm-free, but which my office has a long history 
of trying to rein the horse back in on.
    You mentioned tobacco. Alcohol is one of the top killers of 
folks in our country. I think that again we need to learn from 
our mistakes and be careful about normalization of behavior.
    One of the other dangers about marijuana usage is that we 
do not know what we do not know. And so we do not want to 
conduct this experiment on our citizenry. And that is adults 
and young people. But we know enough about young people to take 
action now, and that is why I focused my efforts and my 
attention in that space at this point in time.
    But again, sir, I do not want anyone to mistake what I am 
saying as implying that these products are considered safe for 
general adult usage.
    The Chairman. Let me ask you about the research, because 
you have both referred to studies that have been done. Are 
there impediments, legal or otherwise, to the study of the 
health effects of marijuana in place?
    Dr. Adams. I will start off just by saying that Secretary 
Azar, the President, and I, have all stated publicly we need to 
make it easier to do research.
    The Chairman. What do we need to do to make that happen?
    Dr. Adams. Well, HHS is partnering with DEA. We are going 
around the country and talking to folks to find out barriers 
that exist to research. One of the things that has been 
announced within the past month was DEA making more strains of 
marijuana available so that folks can test more than just the--
from the one facility in Mississippi, where you could typically 
get strains from.
    But Dr. Volkow is an expert in this area, and NIDA is 
intimately involved in the research process. So I would turn it 
over to her.
    Dr. Volkow. Part of the problem relies on the fact that 
marijuana is a Schedule One. And if you want to do research on 
a Schedule One, you have to get a DEA registration that can 
take, if you are lucky, one year to obtain, and that delays the 
process enormously.
    And every time that you make a change in your protocol, 
that also has to be submitted, and you have to wait for that to 
be approved. So it is a very lengthy, on the ability to get the 
research going. And then once you are going, right now the only 
source for marijuana that is available in our country is that 
that we provide through a contract to Missouri to a farm in 
Missouri.
    So if you as a researcher are interested in a particular 
strain of marijuana, you come to us at NIDA, it is probably 
unlikely that we have it and we will have to cultivate it. So 
the process also is very slow there.
    And finally, to the other component that makes it very 
difficult is that we are interested in understanding what 
people are taking out there. I mean, in the states they are 
legalizing marijuana and there are these dispensaries. And the 
varieties are very distinct.
    And so we do not know the difference between this or that. 
This product is being sold telling that it has this 
characteristic. We cannot fund research that relates to 
products that are actually being bought through these 
dispensaries because it is illegal.
    So we have been working for the past, I would say, several 
years with DEA to try to come up with an accommodation that 
would allow researchers to streamline the process so that they 
can work on an understanding both potentially negative but also 
potentially therapeutic effects of cannabids.
    The Chairman. Well I know Senator Feinstein mentioned some 
legislation that she is working on with Senator Grassley on the 
impediments to research, but that is perhaps something that we 
could work on together.
    Co-Chairman Feinstein. Great. I would love it. Thank you.
    Dr. Adams. Can I give a shout-out to Senator Feinstein? I 
am not allowed----
    The Chairman. Absolutely.
    Dr. Adams. I am not allowed to endorse or comment on 
pending legislation, but I was doing my homework. And you and 
Senator Grassley made a statement in the introduction of your 
legislation. You said medical treatment should be based on 
sound science, and for those who are sick that there are safe 
medications that have been proven effective.
    I could not agree with that more. And I think it is very 
important that folks such as yourself are acknowledging that 
and spreading that word.
    Co-Chairman Feinstein. Thank you.
    The Chairman. Senator Feinstein.
    Co-Chairman Feinstein. Thanks very much, Mr. Chairman.
    And thank you--[coughing], excuse me, I have a little 
throat problem.
    Dr. Adams. I am a doctor. I can help you with that. 
[Laughter.]
    Co-Chairman Feinstein. I may come to you.
    As I understand, investigations are ongoing. To date, 
nearly 1,500 lung injuries have been associated with the use of 
e-cigarettes and vaping products, with 33 confirmed deaths.
    THC has been present in most of the tested samples of these 
cases. Here is the question: Do we have enough research to 
understand the potential impacts of using e-cigarettes and 
vaping devices to consume marijuana products? What is the 
situation? And what happens to the lung when you use it?
    Dr. Adams. Thank you for that question. This is something I 
am terribly concerned about, and that HHS is really mounting an 
all-hands-on-deck response to.
    We have stood up our Emergency Operations Center at CDC. We 
are working with state and local health departments to get 
information in as quickly as possible. And you summarized it 
correctly, ma'am. A large number of these cases have been 
associated with vaping THC, particularly THC that has been 
obtained through the black market, if you will.
    Co-Chairman Feinstein. Explain what happens when you do 
this.
    Dr. Adams. Ma'am, well as an anestheologist I can tell you, 
God did not mean for much of anything besides oxygen to go into 
your lungs. And when you aerosolize oil and then suck it into 
your lungs and let it re-accumulate on the lining of your 
lungs, it can cause all sorts of bad things to happen.
    And I will also tell you, one of the big problems is we do 
not know what is in these pods. A lot of them are made on the 
black market, and the ones that are even made through, quote, 
``legitimate sources'' we do not know all that is contained in 
them. And it is why last December I put out a Surgeon General's 
Advisory warning about the epidemic rise in vaping among young 
people, a 78 percent increase in vaping among students. And I 
pointed out at the time that a third of young people who were 
vaping had reported vaping marijuana.
    So I would say to you, before I turn it over to Dr. Volkow 
that, number one, the FDA and the CDC advised against vaping 
products containing THC.
    Number two, we advised not to modify or add any substances 
such as THC or other oils to products purchased in stores.
    And finally, no amount of marijuana usage during pregnancy 
or adolescence, no matter how it enters the body, is known to 
be safe. And no pregnant woman or young person should be 
vaping.
    Dr. Volkow?
    Co-Chairman Feinstein. Could I ask you a question? Have 
autopsies been done on the lungs of the 33 confirmed deaths? Do 
we know what happens to the lungs?
    Dr. Adams. Ma'am, what I would say is that--and again, I 
used to run a state department of health in Indiana. And one of 
the challenges is that these investigations start at a local 
level, and a lot of times the decisions about which samples are 
going to be collected, and which autopsies are going to be done 
are made before the state department of health is even alerted.
    And then the CDC finds out after that. So one of the big 
things that we are trying to help people understand is that we 
have to have a high index of suspicion. We have got to ask the 
right questions. And we should be doing an autopsy on all of 
these cases.
    Co-Chairman Feinstein. So autopsies have not been done?
    Dr. Adams. On some of them, but not all of them, ma'am.
    Co-Chairman Feinstein. On some of them?
    Dr. Adams. Yes.
    Co-Chairman Feinstein. Well what has been learned from the 
autopsies? What happens to the lungs?
    Dr. Adams. We know that there is damage to the cells of the 
lungs, to the tissues of the lungs. There is a lot of 
misinformation out there. Some of these cases had been reported 
to be associated with Vitamin E, and that was the case for some 
but it actually looks--it is an inflammatory injury. It is 
almost--I am trying to think of a good comparison--but again, 
it is as if a cell----
    Co-Chairman Feinstein. Enough to cause death?
    Dr. Adams. Oh, absolutely, ma'am. Lymphoid pneumonia has 
been found in some of these folks. But in other folks, it is as 
if the cells and the tissue were being eaten away. Again, you 
are putting toxic materials into the lungs that were never 
meant to be inhaled.
    Dr. Volkow.
    Dr. Volkow. Yeah, just basically in medical school they 
teach you that you should never, ever allow lipids to get into 
the lungs because they produce a very massive inflammatory 
reaction. So that's--and since you require the lungs to 
function properly for oxygen to be transferred, this is 
probably one of the reasons why it has had such negative 
effects.
    But I think it is also highlighting how we are approving 
these technologies in ways without recognizing what their 
negative effects are. And you are highlighting the acute 
effects. But, for example, we do not know what may be the 
effects on the function of the lung long term in those cases 
that you do not see this acute presentation.
    Co-Chairman Feinstein. Well let me ask this question. Are 
vaping devices well enough known? Do they bring on death----
    Dr. Volkow. Well, that----
    Co-Chairman Feinstein [continuing]. As it goes into the 
lungs? If you use--I do not know how to ask this question. If 
you use a vaping device, are you more apt to die?
    Dr. Volkow. Not necessarily. You are using a device that 
has quality control. And, for example, one of the things that 
we have done at NIDA is to develop a standard electronic 
cigarette that can be used to determine whether, for people 
that cannot stop smoking, that use of these vaping devices can 
help them actually be able to protect them from the negative 
effects of combustible tobacco.
    So provided that you have standards of quality control, 
both the device as well as the cartridges that you are using 
and the content of nicotine and the products, this device could 
be given as a therapeutic option for those that cannot stop 
smoking.
    Dr. Adams. And can I answer that question in another way, 
ma'am?
    Co-Chairman Feinstein. Yes.
    Dr. Adams. Even the people who are advocates for e-
cigarettes and vaping devices describe them as ``harm 
reduction.'' Less harm does not mean harmless. No young person, 
no pregnant woman, no person who is not currently smoking, 
should even entertain using these devices. Because, again, you 
are taking substances that are in an unknown pod, and you are 
vaporizing them and taking them back into the lungs. And 
whether that is marijuana, or anything else out there, again we 
do not know what we do not know. But we know that those 
substances were never intended to go into your lungs, and they 
can be toxic.
    Co-Chairman Feinstein. Yes. I have particular concern about 
marijuana use by very young children. And the fact that--
reports have shown that it results in a decline in IQ, in poor 
school performance, and higher rates of school absences.
    How prevalent is this?
    Dr. Adams. Let me take that at the 30,000-foot level, and 
then kick it to Dr. Volkow. It is important for us to 
understand, and a lot of folks say, well, I have smoked a 
joint, or I smoked marijuana back in the '80s, back in the 
'70s. The potency is much, much higher. A higher THC content 
equals more danger.
    Number two, not everyone is going to have the same effect. 
Every person is different. And so some people--as we know, some 
people smoke for five years and get lung cancer, and some 
people smoke for 50 years and do not get lung cancer.
    But if you are talking about a child, you want to give that 
child--I have three young kids--the best chance at life.
    Co-Chairman Feinstein. Yes.
    Dr. Adams. And we know that on a population level that the 
cumulative effects of having an entire population, 9 million 
young people using marijuana products is going to be a net 
negative for our country.
    But do you want to get into specifics, Dr. Volkow?
    Dr. Volkow. Yeah, I will just point out, I mean it is not 
surprising in a way because this endogenous cannabinoid system, 
one of the things that it does, it modulates the activation of 
neuronal networks. So when you are hyper-stimulated, it brings 
it down. When you are hyper-inhibited, it brings it up to 
create that certain window of optimal function. So if you are 
taking marijuana, in a way you are filtering many of those 
stimuli. And your development is dependent on those stimuli to 
actually create the final architecture.
    Co-Chairman Feinstein. How does marijuana impact school 
performance? What does it do to the brain?
    Dr. Volkow. The simplest one, it interferes with memory and 
learning. Someone that is stoned cannot remember. And that is 
not just adolescents, that is any adult.
    Co-Chairman Feinstein. I did not know that.
    Dr. Volkow. And as a result of that, if you are a student 
and your job is to learn, and marijuana stays in the body for a 
long time, you are going to have a long-lasting effect in your 
capacity to memorize and you will fail school.
    And that is without addressing the possibility that----
    Co-Chairman Feinstein. Is the memory loss permanent?
    Dr. Volkow. That is a question that there is controversy. 
There is some evidence that there is long-lasting impairment in 
memory and attention by some studies, and others show that 
after several months it recovers.
    And we don't--that is one of the reasons why we are doing 
the ABCD study, to actually, unequivocally determine if long-
term use of marijuana will produce a long-lasting or 
irreversible change in memory, attention, and other process of 
cognition.
    Co-Chairman Feinstein. Wow. Is it because marijuana today 
is stronger, the THC factor?
    Dr. Volkow. That is not going to help at all. The content 
is much, much higher. And the higher the content--it is 
actually three-fold higher overall, and----
    Co-Chairman Feinstein. Wait, wait, wait. I am not trying 
to--three times higher than when?
    Dr. Volkow. Than 2002.
    Co-Chairman Feinstein. Really?
    Dr. Volkow. Yes.
    Dr. Adams. Ma'am, there was a study that looked at 
marijuana from 1995 till 2014, and they saw that marijuana in 
1995 the average strains were about 4.5 percent THC. The 
average strains in 2014 were about 12 percent. So that is where 
we get the three times number. But it is important to remember 
now that dispensaries have marijuana that is testing at about 
20, 25 percent. So that would be five times stronger than 1995.
    And then when you put it into oils and waxes, you can get 
70, 80, 90 percent THC. So I hate comparisons, but something 
that I say to folks that tends to resonate is, that is like the 
difference between having a light beer in 1995 and drinking a 
pint of vodka today. It is literally that much of a difference 
in concentration.
    Co-Chairman Feinstein. I do not think people know that.
    Dr. Adams. I do not think they do either, ma'am.
    Co-Chairman Feinstein. How do we get that out?
    Dr. Adams. Well, again, the Surgeon General Advisory. We 
need you all to help share it at surgeongeneral.gov. Please let 
people know this ain't your mother's marijuana.
    Dr. Volkow. And the other problem that is confounded is 
that when you go and buy a product, you do not actually know 
what the content of 9 THC is. And this particularly becomes 
problematic when you get an edible. You get the chocolate and 
you do not know the content, and so you do not know how much to 
take of it.
    And one of the reasons why people end up in emergency room 
admission with a psychotic episode is because the content is so 
high.
    Co-Chairman Feinstein. Well, now how big a problem is this?
    Dr. Volkow. In terms of emergency department----
    Co-Chairman Feinstein. No, the high content of 
hallucinogenic quality in marijuana today versus 10--excuse me, 
10, 15 years ago?
    Dr. Volkow. It is very problematic. And studies have 
consistently shown, for example, that investigate the negative 
effects of marijuana that the higher the content of 9-THC the 
greater the likelihood that you will have a psychotic episode. 
The greater the likelihood, actually, the risks associated with 
schizophrenia----
    Co-Chairman Feinstein. Which changes the nature of beliefs 
about marijuana. Because most people that I know believe it is 
relatively harmless. And what you are saying is, it is not 
today; that it is much stronger, and that it is much more 
volatile.
    Dr. Adams. Exactly. And Dr. Volkow is an expert and speaks 
on the effects on the individual, and she has, again, spoken of 
her wonderful brain imaging studies. I tend to look at the 
population level. And the metrics we look at are motor vehicle 
accidents going up. Emergency department admissions going up.
    Co-Chairman Feinstein. For marijuana use? You can prove 
that?
    Dr. Adams. Yes, ma'am. The emergency department admissions 
have gone up for accidental ingestions and for people showing 
up with psychosis. We are seeing all sorts of untoward effects 
from marijuana usage, again particularly in young people. But 
real concerning population health trends related to marijuana 
usage.
    Co-Chairman Feinstein. Could you provide us with some 
information? We may want to put out a paper as a result of 
this, and that might be one of the things that we would 
discuss.
    The Chairman. Well I know that has been one of the 
functions of this Caucus in the past, is to issue reports or 
papers on different topics, and certainly that is something we 
ought to consider doing.
    Co-Chairman Feinstein. Because I have young people in my 
family and, you know, you think it is all nothing. Hopefully 
they do not use it, but they sure can talk about it. So I think 
if I am understanding what you are saying, the potential danger 
of marijuana has gone up rather dramatically in the last 10, 15 
years?
    Dr. Adams. The potential danger has gone up, while the 
perceived harm of the product has gone down. And what I was 
quoting in my opening statement was NISDA data that looks at--
that surveys young people from SAMPHSA. SAMPHSA data that 
surveys young people and asks them their perception of the 
dangers of marijuana. And their perceptions of danger are going 
down, particularly in states that have legalized, because they 
see it all around them. While the actual risk, both from a 
scientific point of view and on a population health level, is 
going up.
    Co-Chairman Feinstein. What has California done?
    Dr. Adams. Well, you have got someone from the California 
Cannabis Research Commission who is going to be on the second 
panel.
    Co-Chairman Feinstein. Oh, good.
    Dr. Adams. And I have been out there. I visited U.C. Davis. 
I have visited U.C.S.D. I have been to the L.A. County Health 
Department. I will tell you that all of the health officials I 
have spoken to are terribly concerned about the spike in 
pregnant women who are using.
    We have seen a doubling in pregnant women who report using 
marijuana, and they are concerned about the number of young 
people. It is causing disciplinary problems in schools, and we 
do not know what the long-term health effects are going to be. 
So in your State, ma'am, we are very concerned.
    Co-Chairman Feinstein. So just quickly, how is it more 
concentrated, more volatile, than it used to be?
    Dr. Volkow. The plant itself. I mean, like in biology you 
can determine the content of the active ingredients by breeding 
up varieties that have higher content. And that is how they 
have come up with plants that have higher and higher content, 
manipulating it.
    And now, with the use of resins, you can extract the active 
ingredient and put it in a cartridge----
    Co-Chairman Feinstein. Oh, dear.
    Dr. Volkow [continuing]. And that gives you even higher 
content. So this is just basically genetic, what the 
agricultural business has been doing to try to improve on the 
quality of the plants.
    Co-Chairman Feinstein. So we should not regard it as 
``harmless''?
    Dr. Volkow. Oh, it is not harmless at all. And when you 
were asking about your own state, there were actually showing 
me that one of the emergency departments in one of the main 
hospitals in San Diego where they basically will have an eight-
fold increase in emergency admissions from the cannabis over a 
period of eight years. Eight-fold. It is gigantic.
    Co-Chairman Feinstein. This is not just vaping----
    Dr. Volkow. This is not just vaping----
    Co-Chairman Feinstein. Oh, I thought you said----
    Dr. Volkow [continuing]. And smoking, and edibles, and 
every single way of administering cannabis.
    Co-Chairman Feinstein. So if a mother uses this strong 
stuff while she is pregnant, will that impact----
    Dr. Volkow. She can become psychotic herself. High-content 
THC, what people do not realize is high-content marijuana with 
very high THC can trigger an acute psychotic episode. And that 
leads you to the emergency department. It is a horrible 
experience.
    Co-Chairman Feinstein. What if she is pregnant? What does 
it do to the unborn child?
    Dr. Volkow. Well, you have there, on top of the negative 
effects to the mother, the fact that the marijuana will go into 
the fetus and affect the brain of the fetus. The fetus cannot 
complain, right?
    Co-Chairman Feinstein. Right.
    Dr. Volkow. But it is going to very likely be interfering. 
Imagine that there is this very precise process by which your 
brain determines when this neuron migrates here, when this 
neuron divides, when this neuron interconnects with another, 
and that is modulated by your own endogenous cannabinoid 
system.
    When you artificially stimulate that system, you are 
basically disrupting all of that perfect orchestration. That is 
why we have so much concern about the use of marijuana among 
pregnant women, children, and adolescents.
    Co-Chairman Feinstein. Can a baby be born addicted to 
marijuana?
    Dr. Volkow. I do not know of any description of a baby 
having been born addicted to marijuana. But what we do know is 
that babies can be born sedated because of the use of 
marijuana, particularly during the last trimester.
    But the condition of a baby that is born addicted, that has 
not been something that has been documented.
    Dr. Adams. And ma'am, something that again I was just in 
your state two weeks ago talking about were the infant 
mortality rates. We know one of the predictors of infant 
mortality is low birth weight. Well I was shocked when I saw 
the Colorado PRAMS data that showed that women who smoke 
marijuana have a 50 percent increased chance of having a baby 
born at low birth weight.
    And so that is another thing that people do not think about 
when they are prescribing marijuana to women who are pregnant 
or could be becoming pregnant.
    Co-Chairman Feinstein. Thank you.
    The Chairman. Well, unfortunately we are going to have to 
stop there with the first panel, because we obviously have a 
lot of questions and we want to continue the conversation, but 
we want to get to the second panel, too.
    So thank you, Dr. Adams, Dr. Volkow, for your contribution. 
And, believe me, we want to continue the conversation. Because 
as you can see, Senator Feinstein and I, and I am sure our 
other colleagues who could not be here today, have a lot of 
questions. And I think the American people deserve the facts, 
which is what we are trying to get to here.
    So thank you very much, and we will invite the second panel 
to come forward and get situated, and we will get started in 
just a second.
    Dr. Adams. And, Senator, we are happy to submit any 
information you need about the harms of marijuana usage that we 
have collected. Please share my Advisory, surgeongeneral.gov. 
We need to get the word out to folks that this is not some 
harmless product out there.
    The Chairman. We will do that, sir. Thank you.
    Dr. Volkow. And thanks for doing the hearing.
    The Chairman. Thank you.
    (Pause.)
    Well thank you very much. Our second panel includes experts 
who have conducted research on various aspects of public health 
and marijuana use.
    First, Dr. Robert Fitzgerald, who currently serves as a 
Professor in the Department of Pathology at the University of 
California-San Diego, where he is also the Director of the 
Toxicology Laboratory, Director of the Toxicology Laboratory, 
and Associate Director of the Clinical Chemistry Laboratory. He 
is Board Certified in Toxicology and Clinical Chemistry by the 
American Board of Clinical Chemistry, and his research, Senator 
Feinstein, focuses on marijuana-impaired driving. I know you 
had questions about that.
    Dr. Staci Gruber is Director of the Cognitive and Clinical 
Neural Imaging Core and the Marijuana Investigations for the 
Neuroscientific Discovery Program, otherwise called the MIND 
Program, both housed at the Harvard-affiliated Psychiatric 
Hospital in Belmont, Massachusetts' McLean Hospital. She is 
also an Associate Professor of Psychiatry at Harvard Medical 
School. Her research focuses on cognitive development and the 
effects of marijuana's major constituent compounds.
    Dr. Sean Hennessy is Professor of Epidemiology in Bio 
Statistics at the University of Pennsylvania's Perelman School 
of Medicine. Dr. Hennessy conducts research in the field of 
pharmacoepidemiology. That is a mouthful. Which is the study of 
the health effects of drugs and other medical products in 
populations. Dr. Hennessy is the past Scientific Chair and past 
President of the International Society for Pharmacoepidemiology 
and has served as the FDA's Drug Safety and Risk Management 
Advisory--served on that committee, the Drug Safety and Risk 
Management Advisory Committee for the FDA. Dr. Hennessy 
contributed to the National Academies of Science's 2017 Study 
on Marijuana's Health Effects.
    And finally, Dr. Madeline Meier is the Assistant Professor 
of Psychology at Arizona State University and Post-Doctoral 
Fellow, with support from the Duke University Trans 
Disciplinary Prevention Research Center. Her research interests 
involve adolescent marijuana use, as well as the health effects 
of marijuana concentrates.
    So obviously there is a lot of interest in what you have to 
say. If I could first recognize Dr. Fitzgerald and ask each of 
you maybe to speak for about five minutes, and then maybe be 
open to some questions. Your written remarks will be made part 
of the record, without further ado.
    So, Dr. Fitzgerald.

STATEMENT OF ROBERT FITZGERALD, Ph.D., PROFESSOR OF PATHOLOGY, 
         UNIVERSITY OF CALIFORNIA-SAN DIEGO, CALIFORNIA

    Dr. Fitzgerald. Thank you, Senator, Senator Feinstein. It 
is a pleasure to be here today to discuss issues related to 
marijuana and driving.
    As a way of brief introduction, my first job out of 
graduate school was as a forensic toxicologist from the State 
of Virginia where I helped work with the medical examiner to 
determine the cause and manner of death in medical examiner's 
cases.
    At the ME's office, I saw the devastating effects of 
driving under the influence on a routine basis. I also had the 
opportunity to work with both state and local law officers, 
along with prosecution and defense, to present scientific data 
in courts of law.
    Currently I am a clinical toxicologist at UC-San Diego 
where my research focuses on developing analytical methods to 
measure concentrations of THC and metabolites following recent 
marijuana exposure.
    I am part of a large team of investigators at the 
University of California-San Diego's Center for Medical 
Cannabis Research focused on understanding both beneficial and 
detrimental effects of cannabis on human health. We recently 
completed enrolling subjects in one of the largest studies to 
date looking at the effect of smoked marijuana on driving 
performance, and are in the initial stages of analyzing this 
data.
    The relationship between marijuana use and driving 
impairment is complex because of the unique pharmacokinetics--
that is the time course in the body, and pharmacodynamics--that 
is its physiological effects--of THC.
    With ethanol there is a clear relationship between amount 
consumed, blood concentrations, and effect on driving. With 
marijuana, these types of relationships are much more complex.
    The relationship between blood THC concentrations and crash 
risk has not been established. But there is a clear 
understanding that THC impairs driving performance. The 
question that remains is how to best identify drivers who are 
impaired by marijuana. There are no perfect solutions, and 
legislative directives must balance keeping our roadways safe 
with due process.
    The problems with determining the relationship between 
concentrations of THC and impairment is that levels of THC vary 
widely depending on the route of administration, the time of 
sampling after dosing, and the characteristics of the 
individual consuming.
    Generally, smoked marijuana causes effects that start 
shortly after inhalation and last for about three hours. While 
subjects who eat marijuana start feeling effects about an hour 
later, and can have effects up to eight hours later.
    Unlike alcohol, which is cleared within 24 hours of 
drinking, THC and several metabolites accumulate in the body 
with repeated dosing. So frequent users have baseline 
concentrations of THC that exceed the per se limits in many 
states.
    After smoking, THC concentrations in blood change rapidly. 
And our studies have documented the poor relationship between 
concentrations of THC and measures of impairment. Studies like 
this led the National Safety Council to put out a Position 
Statement in 2017 that reads: ``It is further concluded that, 
due to rapid changes in blood THC concentrations over time, 
there is no minimum safe threshold blood concentration below 
which a driver can be considered to have been unaffected while 
driving following recent marijuana use. Consequently, there is 
no scientific basis for the adoption of THC per se laws for 
driving.''
    This statement was also supported by the International 
Association of Chiefs of Police. Despite these position 
statements, 18 states currently have some form of per se 
statutes.
    How do we keep our roads safe? In California, prosecution 
of driving under the influence of drugs is currently based on 
officer observations combined with toxicology testing. This 
practice will likely continue for the foreseeable future.
    Since there is no reasonable expectation that THC or a 
metabolite of THC will be useful for per se impairment, an 
alternative approach would be to develop methods that identify 
recent use. The biological specimens that could be used to 
determine if a driver has recently used marijuana are blood, 
breath, and oral fluid.
    The primary advantage of breath and oral fluid over blood 
is that they can be collected at the roadside at the time of a 
traffic stop, as opposed to blood which typically takes about 
90 minutes to collect.
    This is an important consideration because, unlike ethanol, 
concentrations of THC fall by more than 90 percent in that 
short time frame. There is a variety of ongoing efforts to 
identify recent-use markers.
    In respect to my time limit, I would like to close my 
initial statement by mentioning two items that I think this 
Caucus needs to be aware of so they can help shape appropriate 
regulations.
    Due to federal restrictions, investigators cannot study the 
cannabis products our population is exposed to. As Dr. Adams 
indicated, we have unleashed a massive experiment that is sort 
of uncontrolled in our population, and our most powerful 
resources, our research community, has limited ability to study 
that.
    This is a critically important public health issue that 
needs to be changed. Currently there is no standardized data 
collection for driving under the influence of drugs. Without 
good data, it is difficult to develop good policy.
    I hope my testimony was helpful and look forward to 
answering questions. Thank you.
    The Chairman. Thank you very much. Dr. Gruber.

  STATEMENT OF STACI GRUBER, Ph.D., PROFESSOR OF PSYCHIATRY, 
         HARVARD MEDICAL SCHOOL, BOSTON, MASSACHUSETTS

    Dr. Gruber. Thank you, Senator Cornyn and Senator 
Feinstein, and members of the Caucus who may tune in later to 
see this----
    Co-Chairman Feinstein. Could you speak directly into the 
microphone?
    Dr. Gruber. Certainly. Is that better?
    Co-Chairman Feinstein. Yes.
    Dr. Gruber. I should be better at this.
    So as you have heard, and as we know, the Nation is in the 
midst of a green rush, and marijuana or cannabis headlines 
flood news outlets daily. Yet it is often difficult for people 
to read through study findings and make sense of what we know 
and what we do not.
    Despite the fact that 33 states have fully legalized 
medical marijuana, and another 15 have limited medical 
marijuana laws, leaving only 2 states without access, nearly 
all of what we know about the impact of marijuana comes from 
studies of recreational marijuana users.
    These studies typically focus on those with chronic, heavy 
marijuana use. Data across studies is somewhat inconsistent, 
but generally reflect differences between those who use 
marijuana and those who do not spanning a number of areas that 
we have heard allusions to already, including cognitive 
performance. Domains most commonly affected include memory and 
executive functioning. For example, the ability to inhibit 
inappropriate responses, or to use feedback to change one's 
behavior. These are reportedly impacted by marijuana use.
    Earlier onset of marijuana use, as well as higher frequency 
and magnitude of use, are also associated with greater 
difficulty on these tasks. And studies of brain structure and 
function have also reported deficits or differences between 
marijuana users and non-users, specifically as among early 
onset or adolescent users of marijuana.
    This is not surprising. As you heard from Dr. Volkow, we 
know that during adolescence the brain is neuro-developmentally 
vulnerable. That is, it is under construction. It is sensitive 
not just to marijuana but to other substances--alcohol, 
illness, injury.
    Another concern that we have heard a lot about today is the 
rising potency of marijuana products. Particularly problematic 
for youth, our most vulnerable consumer group, THC, the primary 
intoxicating compound of the plant has increased 300 percent, 
or more than three-fold, in flower products since 1995. And 
these novel concentrate products that we have also heard 
illusions to, Dabs, Shatter, Wax, you have heard these terms, 
THC levels of these products go at least up to and sometimes 
north of 90 percent.
    Cannabidiol, or CBD, may mitigate some of the negative 
effects that we see from THC, but it is virtually undetectable 
in recreational products today. Thus far there have been no 
studies that have directly assessed the impact of potency or 
novel versus conventional products in either recreational 
consumers or medical patients.
    It is also important to remember that not all marijuana use 
is the same. And our recreational marijuana consumers are not 
the same as our medical marijuana patients.
    For example, their goal of use is wholly different. Our 
recreational marijuana consumers--I have spent nearly 30 years 
with these folks--their goal is to change their current state 
of being, or to get high. Our medical marijuana patients are 
not interested in getting high. They use to alleviate symptoms. 
They say things like I want to sleep through the night. I would 
like to be able to take a drive with my son. I want to go for a 
walk with my kids.
    As a result, their product choices are often different. 
Recreational consumers often choose products very high in THC. 
Our medical patients choose products that may be high in THC 
but often contain other compounds, things like cannabidiol or 
other non-intoxicating compounds.
    Cannabis and cannabinoids have demonstrated therapeutic 
potential for a number of indications. We heard reference to 
the 2017 National Academy's report noting conclusive or 
substantial evidence that cannabis or cannabinoids were 
effective for, quote, ``the big three, chronic pain, nausea and 
vomiting as a function of chemotherapy, and muscle spasticity 
as a function of MS.
    We also know that epadadialexis or purified CBD extract was 
approved for pediatric onset intractable seizure disorders. But 
despite the fact that medical cannabis has been legal since 
1996, data regarding the impact of medical marijuana treatment 
is severely limited. Preliminary evidence from the very first 
longitudinal studies of medical marijuana patients demonstrate 
improvements in some areas of cognitive performance, including 
areas noted to be impaired in those with recreational use.
    We also see improvements in clinical state, better sleep, 
decreased pain, and notable reductions in the use of 
conventional medications including opioids, so important in the 
midst of this crisis.
    When it comes to marijuana, one size does not fit all. We 
have a single term, marijuana, and we often hear it used to 
refer to anything like the whole plant or individual compounds 
from the plant, intoxicating or not, which mean very different 
things.
    Current regulations around marijuana limit the type and 
scope of research projects we can do. And, contrary to popular 
belief, we cannot currently study the impact of products that 
patients and consumers are actually using via clinical trial 
models, significantly reducing external or ecologic validity.
    Further, as Dr. Volkow testified, the Schedule One status 
of marijuana leads to a number of obstacles in conducting 
research. Policy at this point has clearly outpaced science. 
And as the Nation has warmed toward both the use of medical and 
recreational marijuana, the need for empirically sound data is 
critical in order to maximize benefit and reduce harm.
    Regardless of how you feel about marijuana, science and not 
emotion or rhetoric must be our guide. We have a responsibility 
to provide the best and most accurate data to our medical 
marijuana patients, our recreational consumers, our health care 
providers, and the general public so they can make the best, 
most informed decisions about marijuana use.
    At this point, I would thank you for your ongoing efforts 
and being willing to help move things forward. Thank you.
    The Chairman. Thank you, Dr. Gruber. Dr. Hennessy.

   STATEMENT OF SEAN HENNESSY, PHARM.D., Ph.D., PROFESSOR OF 
  EPIDEMIOLOGY, UNIVERSITY OF PENNSYLVANIA PERELMAN SCHOOL OF 
              MEDICINE, PHILADELPHIA, PENNSYLVANIA

    Dr. Hennessy: Good afternoon, Senators. My name is Sean 
Hennessy and I am a Pharmacist Epidemiologist at the University 
of Pennsylvania. I was a member of the 16-person committee that 
wrote this 468-page report entitled ``The Health Effects of 
Cannabis and Cannabinoids'' that the National Academics of 
Science, Engineering, and Medicine released in January 2017.
    The report is a comprehensive review and synthesis of the 
then-existing literature about the potential health effects, 
both therapeutic and harmful, of cannabis and cannabis-derived 
products.
    The report lists nearly 100 different conclusions about 
these effects. It also discusses four barriers to conducting 
research on cannabis and makes four recommendations on how to 
address research gaps.
    I would like to summarize this report as 6-4-4. Six health 
effects with high-level evidence. Four challenges to conducting 
research. And four recommendations to moving forward. So among 
the highest levels of evidence about the health effects of 
cannabis we made the following conclusions.
    One, cannabis use prior to driving appears to increase the 
risk of motor vehicle crashes, as we have heard about today.
    Two, in states where cannabis is legal, there is an 
increased risk of unintentional cannabis overdose in children.
    Three, pregnant women who smoke cannabis increase the risk 
that their baby will be born with lower birth weight.
    Four, initiating cannabis use at a younger age is a risk 
factor for developing problematic cannabis use later in life.
    Five, long-term cannabis smoking increases the risk of 
chronic breathing problems. And six, some people with chronic 
pain or muscle spasm from multiple sclerosis can obtain relief 
of their symptoms using cannabis-based products.
    Most of the studies for these uses examined orally 
administered cannabis extracts, rather than smoked cannabis. 
The report also identified the following four challenges to 
conducting research on the health effects of cannabis.
    One, there are specific regulatory barriers, including the 
classification of cannabis as a Schedule One substance that 
impede research.
    Two, it is difficult for researchers to gain access to the 
quantity, quality, and type of cannabis product that they need 
to conduct research.
    Three, it is difficult to obtain funding to support 
cannabis research. And four, improvement and standardization in 
research methods are needed.
    Finally, the report makes the following four 
recommendations:
    One, public health agencies and other groups should fund a 
national cannabis research agenda.
    Two, agencies of the U.S. Department of Health and Human 
Services should convene a workshop to develop a set of federal 
standards and benchmarks to guide high-quality research on 
cannabis.
    Three, federal, state, and local health authorities should 
fund improvements to the public health surveillance system.
    And four, the CDC, NIH, FDA, and others should convene a 
committee to characterize regulatory barriers and propose 
strategies to develop the resources and infrastructure that are 
needed to conduct cannabis research.
    I thank you for your attention and the opportunity to 
discuss these important issues, and look forward to answering 
your questions.
    The Chairman. Thank you, Dr. Hennessy. Dr. Meier.

  STATEMENT OF MADELINE MEIER, Ph.D., ASSISTANT PROFESSOR OF 
      PSYCHOLOGY, ARIZONA STATE UNIVERSITY, TEMPE, ARIZONA

    Dr. Meier. Good afternoon, Mr. Chairman and Senator 
Feinstein.
    Co-Chairman Feinstein. Could you speak directly into the 
mike? It is hard to hear.
    Dr. Meier. Thank you for inviting me to contribute to my 
knowledge about cannabis effects on cognitive functioning.
    The most comprehensive study of cannabis use in cognitive 
functioning was published by our group in 2012. Today I am 
going to describe that 2012 study and explain the findings, why 
they are important, and what additional research is needed.
    We have studied the association between persistent cannabis 
use over time and change in IQ from childhood to adulthood. And 
we asked whether cannabis effects on IQ were concentrated among 
adolescent onset cannabis users. That is, cannabis users who 
began using before age 18.
    Data came from the Dunedin Study, which is a study of 1,000 
children born in 1972 and '73 in Dunedin, New Zealand, and 
followed from birth to age 38, with 96 percent of the sample 
taking part in the study at age 38.
    IQ was tested at age 13, before anybody in the cohort had 
started using cannabis, and again at age 38 after some members 
of the cohort had been using cannabis for years. We found that 
persistent cannabis use from ages 18 to 38 was associated with 
decline in IQ. And this decline in IQ was concentrated among 
adolescent onset persistent cannabis users. These are cannabis 
users who began using cannabis before age 18 and continued 
using for many years thereafter.
    Specifically, individuals who began using cannabis in 
adolescence before age 18, and used it for years showed an 
average 8 point IQ decline from childhood to adulthood. 
However, individuals who used cannabis short-term in 
adolescence showed only weak evidence of IQ decline.
    Further, individuals who began using cannabis in adulthood 
sometime after age 18 did not show decline in IQ even when they 
used persistently.
    Quitting or reducing cannabis use did not fully restore 
intellectual functioning. Decline in IQ could not be explained 
by alcohol or other drug use, or by reduced years of education 
among cannabis users.
    Decline in IQ could also not be explained by low childhood 
socioeconomic status or poor childhood self-regulation. Friends 
and relatives reported noticing more attention and memory 
problems in everyday life among the persistent cannabis users. 
These findings are important for a number of reasons.
    First, an especially important feature of this study is 
that we had IQ test data from both before and after study 
members started using cannabis. This allowed us to rule out the 
possibility that IQ deficits in cannabis users predate the 
onset of cannabis use.
    We showed that regardless of their IQ test performance in 
childhood, adolescent onset persistent cannabis users performed 
worse than nonusers, and worse than adult onset cannabis users 
on IQ tests in adulthood.
    Second, the eight-point IQ decline we observed among 
cannabis users who began using cannabis in adolescence and 
continued using for many years is non-trivial. For example, an 
average person has an IQ of 100, placing them in the 50th 
percentile for intelligence, compared to same-age peers. If 
this average person loses 8 IQ points, they drop from the 50th 
to the 29th percentile for intelligence.
    Third, IQ is a predictor of a person's access to a college 
education, their lifelong total income, their access to a good 
job, and their performance on the job. Individuals who lose 8 
IQ points may be disadvantaged relative to their same-age peers 
in many important aspects of life. In fact, the adolescent 
onset persistent cannabis users from our 2012 study ended up in 
occupations that were less prestigious, less skilled, and less 
well paid than their parents' occupations.
    Finally, only about 2 percent of the sample became those 
adolescent onset persistent cannabis users. Thus, any effect of 
cannabis on IQ is confined to a relatively small segment of the 
population. Nonetheless, findings are concerning given that 
fewer adolescents today believe that regular cannabis use 
presents a serious health risk.
    Additional research is needed to answer the following 
questions:
    One, what are the mechanisms underlying cannabis-related IQ 
decline?
    Two, what are the parameters of cannabis use that determine 
the magnitude and persistence of cognitive deficits? These are 
things like frequency, duration, quantity of use, and potency.
    Three, does cognitive functioning recover with abstinence?
    Four, are there individual differences in susceptibility to 
cannabis-related cognitive deficits?
    To answer these questions, we need large-scale longitudinal 
studies to follow use from before to well after cannabis 
initiation, and to combine cognitive testing with brain imaging 
to better understand the mechanisms that might underlie 
cannabis-related decline in IQ.
    The Adolescent Brain and Cognitive Development Study was 
launched in part to meet this need. Thank you.
    The Chairman. Thank you, Dr. Meier.
    Welcome, Senator Rosen. Thank you for joining us. Let me 
start with a five-minute round of questioning.
    Dr. Gruber, just a point of clarification. We heard from 
the previous panel that THC concentrations in recreational 
marijuana have at least tripled. But I see in your paper you 
say that you believe it has quadrupled from 1995 to 2017. Is 
that correct?
    Dr. Gruber. I think the prior panel referenced the paper 
that was published----
    I think the prior panel referenced the paper that was----
    Co-Chairman Feinstein. Louder, please? I'm sorry.
    Dr. Gruber. Sure. Is that better? I think the prior panel 
referenced the publication from 2014----
    The Chairman. Oh, okay.
    Dr. Gruber. At that time, the difference from '95 to 2014 
was about three times.
    The Chairman. Three times?
    Dr. Gruber. Right now, the average potency across the 
Nation from government-seized products is about 17 percent. 
That is contrasted to about just under 4 percent in 1995.
    The Chairman. Okay, so that is significant. You think the 
best information is it has quadrupled in concentration?
    Dr. Gruber. I would say in terms of national averages for 
THC, that is right.
    The Chairman. But----
    Dr. Gruber. Those were recreational products.
    The Chairman. But you also point out--and this is really 
the point I wanted to get to--is that there are concentrates, 
other products that have been created. You mentioned things 
like Dabs, the colloquial name for concentrated oil, created by 
extracting THC from flower-based marijuana products, Shatter 
Wax, Butter, and others, that all have a significantly higher 
concentration potency compared to conventional marijuana 
products as high as 80 percent more concentrated. Is that 
correct?
    Dr. Gruber. Or higher, absolutely right. This is the 
recreational market that is very focused on increased THC 
because if the goal of use is to become intoxicated, or to 
change your current state of being, you are looking for 
products that will deliver that bigger bang for the buck, if 
you will. So these products are very, very popular and becoming 
more popular across the Nation in the recreational market.
    The Chairman. Well it strikes me as significant. If you 
smoke it, it is about four times more powerful than it was in 
1995. But you can take it in a concentrated form that could be 
80 percent of traditional marijuana product.
    Dr. Gruber. Exactly. THC is significantly higher, as we 
heard from our first panel, significantly higher these days 
than in prior years.
    The Chairman. Well I can imagine just from a scientific 
standpoint trying to figure out what the dosing is, and what 
the effect of a dose is very difficult given the range of ways 
that people can get access to the active ingredient.
    Dr. Gruber. Mode of use is very important in terms of onset 
of effects and duration of effects. Absolutely true. Especially 
important for our medical cannabis patients.
    The Chairman. Dr. Fitzgerald, you have done a lot of work, 
you said, in terms of its impact on impaired drivers. Would it 
be fair to say that the concentration of THC and whether it is 
consumed from recreational use of smoking marijuana compared to 
these concentrates? Does it have a--is there a correlation 
between the concentration of the product that you consume and 
the level of impairment for drivers?
    Dr. Fitzgerald. So I think that is one of the issues that 
Dr. Adams brought up, as well, is that we have not even been 
able to study the Dabs and the concentrates. It is not possible 
to do those studies, currently.
    The Chairman. But those are not standardized products? I 
mean, like you would be able--you cannot compare widgets to 
widgets, I guess.
    Dr. Fitzgerald. Correct.
    The Chairman. Because they are all sort of concocted by 
whoever makes them, according to their own recipe, and the 
like.
    Dr. Fitzgerald. Several issues there. One, we do not know 
what is actually in those. They are labeled. California 
actually does have a reasonably good laboratory system for 
analyzing plant materials, as well as Dabs and things for 
pesticides and concentrations of THC. But that is only in the 
legal market. And the legal market, unfortunately, is a small 
share of the total market of recreational marijuana.
    The Chairman. As we know, there has been an unfortunate 
increase in suicides in the country, a lot of concerns about 
our Veterans in particular, but not just Veterans. It is just 
young people and others who end up taking their life.
    I wonder, do you find any correlation between self-
medication of people with underlying mental health disorders 
that get exacerbated by the use of marijuana or some of these 
concentrated products?
    I do not know who would be the most appropriate person to 
ask. If you have an opinion, please jump in.
    Dr. Gruber. I have an opinion, since I work in a 
psychiatric hospital and have been seeing the patients for 
about 30 years.
    The Chairman. It sounds to me like you are qualified.
    Dr. Gruber. Maybe, I don't know. It's under debate. I can 
tell you that there are many, many patient populations that 
derive real benefit from using cannabis or cannabinoid-based 
products. And the potential risk for individuals with 
undiagnosed conditions or disorders--you know, where we hear 
about these individuals who are using and not necessarily 
disclosing, or they are self-medicating. One of the important 
things to be mindful of is that it is not necessarily the 
cannabis. But we have to be mindful of what is driving the 
cannabis use.
    Individuals who have different types of conditions, as I 
mentioned, often get benefit from use. But it is very, very 
important to watch these people over time and to look at the 
impact versus, you know, sort of a cross-sectional assessment, 
in a longitudinal fashion.
    No doubt some individuals with differing conditions have 
their conditions exacerbated by cannabis use. That is why it is 
so important to be able to identify the most likely compounds 
from the plant which may make things worse versus those which 
may make things better.
    In fact there is evidence to suggest some compounds from 
the plant may actually really positively impact some of these 
conditions that we see. And this is why so many people are 
turning toward them. But without real empirically sound data to 
guide these types of studies, we have limited ability to give 
them information.
    The Chairman. Well my understanding, my layman's 
understanding, is that there is some evidence that epilepsy can 
be treated using THC-related products.
    Dr. Gruber. Cannabidiol.
    The Chairman. Okay. Is there any--what other benefits have 
you been able to identify based at least on anecdotal 
information, in the absence of these longitudinal studies? What 
other benefits do you suspect may be derived from use of 
marijuana?
    Dr. Gruber. So different compounds from the plant may very 
well have individualized benefits. We know about cannabidiol. I 
think this was mentioned in your bill. Cannabidiol has been 
shown to potentially be efficacious not just for epilepsy, 
which is now approved by the FDA, Epidialial Schedule Five, but 
for other conditions. There have been some interesting studies, 
including preclinical work, in areas like anxiety. A number of 
different conditions may be positively impacted by cannabidiol. 
Other compounds may yield, again, therapeutic potential, but we 
do not have much in the way of long-term studies. And 
unfortunately, it is very difficult to study these compounds 
using clinical trial models, sort of the gold standard for 
deriving empirically sound data, given our current 
restrictions.
    We have an ongoing--we just started a long-term clinical 
trial, open label to double-blind, of a whole plant full 
spectrum product for patients with anxiety. This data will be 
very, very important since so many people turn to things like 
CBD and they say it is good for this, it is good for this, and 
it would be great to have empirically sound data to lean on to 
actually guide patients and care givers.
    The Chairman. I even have a friend who said they put CBD 
product in their pet food----
    Dr. Gruber. Sure.
    The Chairman [continuing]. So their pet--it relieves their 
pet of anxiety. So I guess it cures everything.
    Dr. Gruber. I do not know about everything, but there is 
some data from studies outside of this country, small studies, 
in terms of cannabidiols' impact on anxiety, some pre-clinical 
work, and finally some work here. So it certainly begs the 
question of how much more we need, which in my opinion is a lot 
more. But we are starting.
    The Chairman. Thank you. Doctor--Doctor Feinstein? Senator 
Feinstein. (Laughter.]
    Co-Chairman Feinstein. Thank you. Thirty-three states and 
the District of Columbia have legalized marijuana in some form. 
And each state has its own laws and regulations.
    Should we be concerned that the lack of uniformity across 
states in terms of testing, labeling, packaging, the strength 
of products that may be sold, how they may be advertised, and 
how they may be accessed, can lead to consumer confusion? And 
this could produce unintended acute public health effects, 
including increased emergency room visits.
    In Colorado, for example, there was a three-fold increase 
in marijuana-related emergency room visits between 2012 and 
2016. So here is the question:
    Would uniform regulations across states be helpful to 
ensure consumer safety and reduce public health impacts such as 
emergency room visits associated with marijuana use? Who would 
like to go--why don't we just go right down the line. If you 
have a comment, make it. If you do not, you do not.
    Dr. Fitzgerald. Yes, certainly I think California is a 
model there for the fact that all the state-approved marijuana 
has actually been through a very sophisticated testing scheme 
to show its purity, show that it does not have pesticides, show 
it does not have fungus, and those things. There is some 
question about the reliability of different laboratories, and 
it would be nice to have a reference laboratory that everyone 
else sort of standardizes against. That would be useful to have 
uniform labeling. And certainly the CDC can be helpful in that 
regard.
    Co-Chairman Feinstein. Thank you.
    Dr. Gruber. I think it is incredibly important to have 
uniformity.
    Co-Chairman Feinstein. I am having trouble hearing you.
    Dr. Gruber. I think it is incredibly important to have 
uniformity, and even more important to have full disclosure of 
``what's in your weed''? People have no idea very often what 
they are getting. So I think it is incredibly important, since 
states make their own, sort of their own rules and regulations 
about what is allowed.
    In my State of Massachusetts--and I spend a lot of time in 
California as well--these things are clearly defined in terms 
of testing for aflatoxins, heavy metals, pesticides, 
contaminants, yeast, mold----
    Co-Chairman Feinstein. So a standard across the United 
States would be helpful?
    Dr. Gruber. I think having a reference standard would be 
incredibly important in making sure every state does thorough 
testing is critical.
    Co-Chairman Feinstein. Thank you.
    Dr. Hennessy. I agree. I do not have anything to add.
    Co-Chairman Feinstein. Thank you.
    Dr. Meier. I agree, as well, and do not have anything 
additional to add.
    Co-Chairman Feinstein. Okay. What is the most common form 
of marijuana concentrate being used by adolescents? And how 
much THC does it contain? Adolescent use is my big concern.
    Dr. Meier. My group just published I believe the first 
epidemiological study of that. And we found that you can talk 
about concentrates as a general class, but there are two really 
different types of concentrates--one that is extracted using a 
solvent like butane--and those tend to have generally higher 
concentrations than the other class of concentrates where the 
THC is extracted using ice, or just rubbing it. And that has 
still much higher THC content than, for example, marijuana 
which is the buds of the cannabis plant. And that adolescents 
are using all of that. But primarily they are using the 
solvent-extracted----
    Co-Chairman Feinstein. They are using the what?
    Dr. Meier. The solvent-extracted concentrates.
    Co-Chairman Feinstein. What is that?
    Dr. Meier. Which go by names, various names. Dabs is the 
generic name to refer to just taking a very small kind of waxy 
piece of the concentrate. But then there's Butane Hash Oil, or 
they call it BHO, and it is called that because you extract the 
concentrate with butane solvent.
    It is also called ``Honey Oil,'' ``Crumble,'' lots of 
different names for it. And while those products look 
different, one can look like a waxy sticky substance, one can 
look like butter, they all contain similarly high levels of 
THC.
    Co-Chairman Feinstein. Ah-hah. So are they heavily used by 
adolescents?
    Dr. Meier. We know from the State of Arizona one in four 
adolescents have said they have tried concentrates.
    Co-Chairman Feinstein. So what would you suggest we do, if 
anything?
    Dr. Meier. I think we need--my primary concern is educating 
parents and people like you to recognize what a concentrate is. 
It does not look like marijuana. It looks very different, and 
recognizing that that contains very high levels of THC which 
could pose risks to health.
    Co-Chairman Feinstein. Well would you have a standard for 
this? Does that makes sense? Or should government get involved 
in this? I think, you know, when you talk about adolescents, 
you do not want them to die and you do not want them to become 
addicted.
    Dr. Meier. Correct. We do not want them to become addicted. 
But we still need to do research on whether adolescents who use 
concentrates are more likely to become addicted than if they 
use the lower THC marijuana.
    So I think we need more research, because some evidence 
suggests that it is possible that these concentrates will not 
have ill effects if adolescents are titrating their use, which 
means using less when the THC content is high.
    Co-Chairman Feinstein. Thank you. Thanks, Mr. Chairman.
    The Chairman. Senator Rosen.
    Senator Rosen. Well thank you. I want to thank Chairman 
Cornyn, Ranking Member Feinstein, for holding this important 
hearing. I want to thank all of you for your years of school 
and research and dedication to this extremely important topic.
    I want to talk a little bit about medical marijuana. 
Although marijuana is legal in Nevada for both medicine and 
recreational purposes, the research that you are doing is so 
important for my state's hospitals, providers, schools, 
parents, law enforcement agencies, anybody that is concerned 
with the public health impact. And there are approximately in 
Nevada about 17,000 medical marijuana patients.
    So this research that you do really impacts their lives, 
their ability to seek treatment for their medical conditions. 
And so with that in mind, I really appreciate the bipartisan 
approach which has led to this hearing, and I hope the 
conversation will continue to be research and science based. It 
is so important that we have these longitudinal studies, 
epidemiological studies, so on and so forth. It makes a real 
difference as to how our communities can educate and legislate, 
if we need to, to do the right thing.
    But I want to talk about the potential benefits of medical 
cannabis in treating our Nation's Veterans. We have over 
220,000 Veterans in Nevada. And, let me tell you, I do not have 
to tell you how much they do struggle. They struggle with 
chronic pain. They struggle with depression, anxiety, post 
traumatic stress symptoms, and in too many cases they are 
becoming addicted to medications prescribed to them--opioids, 
other things like that.
    Our Veterans have given so much to their country, they just 
want to come back. They want to claim their lives and continue 
to serve their communities in whatever way is good for them and 
their families.
    And so VA providers are currently prohibited from 
recommending or prescribing cannabis use. The VA will not 
reimburse Veterans for medical marijuana prescriptions from any 
source.
    Former VA Secretary David Shulkin, he stated last week he 
believes the VA should be involved in research and anything 
that could potentially help Veterans and their wellbeing.
    So to Dr. Hennessy, and then anyone else after, you were a 
member of a committee that conducted rigorous overview of 
available research on the potential health benefits of 
cannabis, or therapeutic benefits. It also identifies barriers 
to research and you made recommendations.
    So I would really appreciate your thoughts of how we might 
use cannabis to help our Veterans through anxiety and 
depression in those ways, and find alternatives to treat the 
issues that they are suffering from when they come home.
    Dr. Hennessy. So thank you for your question, Senator. So 
of the uses that you mentioned, there is randomized trial data 
supporting the use of cannabis products for chronic pain. And 
the cannabis products that were studied most often for chronic 
pain was an oral solution of one-to-one THC to CBD. It was not 
either smoked or vaped cannabis.
    The other indications that you mentioned, anxiety, 
depression, PTSD, there are not good data from randomized 
trials that support the efficacy of either whole cannabis or 
cannabis-derived products for those indications.
    Lack of evidence does not mean that the products are not--
that none of the constituents of cannabis are not effective. In 
some cases it merely means that the studies have not been 
conducted, or not enough of them have been conducted to 
identify a beneficial effect, if there is one.
    Senator Rosen. But you would support us funding, or lifting 
the ban on some of the research to find out if we can use these 
products effectively, Dr. Gruber?
    Dr. Gruber. Yes. And thank you so much for focusing on this 
issue. We have a program through the MIND program called 
Serving Those Who Have Served. And it is dedicated to our 
Veterans. Because so many are already using cannabis of 
cannabanoids for treatment, many are interested in using it. 
But we have no real data.
    Senator Rosen. Right.
    Dr. Gruber. So, you know, we come at this as a quasi 
clinical trial because we cannot administer products that are 
in the marketplace, given our current federal regulations and 
restrictions. So we do the best that we can.
    But we followed these folks over time, longitudinally. And 
we need more data like that to be able to really understand the 
impact. As referred to by Dr. Hennessy, we do not have a ton of 
data. But certainly lifting anything that would allow greater 
research efforts to be made I would be in favor of.
    Senator Rosen. Well thank you. I want to--you spoke about 
chronic pain, and I was fortunate enough to be able to start 
the Comprehensive Care Caucus, which is focusing on palliative 
care, people living with a terminal illness or chronic disease, 
and they need palliative care, although they may not be getting 
curative care.
    And so can you speak to the effects of how we could use 
cannabis in the palliative care spectrum for those, as I said, 
living with chronic disease, or living longer with terminal 
illness, to relieve some of the symptoms that they may be 
having as a result of their disease?
    Dr. Hennessy. Sure. So one of the symptoms that patients in 
palliative care experience is chronic pain. And as I mentioned, 
there are clinical trials showing that oral solutions of 
cannabis extract are effective for chronic pain.
    In terms of other indications for use in the palliative 
care setting, I think more research is needed to be able to 
recommend them as effective therapies. We do not want to 
recommend therapies and offer false hope to people for 
therapies that end up not being effective. That, in addition, 
has side effects on their own.
    Senator Rosen. Right. Thank you.
    Dr. Gruber. I think it is also important, just to dovetail 
on what Dr. Hennessy is saying, to be able to assess the actual 
products that patients are using, as opposed to just sort of 
guessing. And the one-to-one ratios of oral solutions, things 
like Sativex, are not necessarily in the marketplace for our 
palliative care patients.
    Our ongoing longitudinal study at the MIND program actually 
follows patients with chronic pain as a subgroup, and they 
demonstrated improvements over time using lots of different 
products. But this research is really in its infancy, and this 
is, as far as I know, the only longitudinal study like this in 
the country.
    Senator Rosen. Right.
    Dr. Gruber. We need a lot more.
    Senator Rosen. Well I applaud all of your work, and I do 
think that particularly in the medical space trying to find the 
ways that we can use marijuana, whether for chronic pain, 
anxiety, terminal disease, PTSD, depression, if we can find 
ways that make people--help them go better through their lives, 
then it is definitely worth researching. And I appreciate your 
hard work. Thank you.
    The Chairman. Thank you, Senator Rosen.
    Dr. Gruber, I think I understand what you were telling me 
earlier. Let me just confirm I got this right. There is a part 
of marijuana that will make you high. That is THC, right? The 
active ingredient?
    Dr. Gruber. That is the primary psychoactive compound in 
the plant, yes.
    The Chairman. Okay, that is a more eloquent way of saying 
it than I did. And then there are other products from the 
marijuana plant, or that can be derived from that, like CBD 
that you think has some medicinal or beneficial effects? But 
that has little or no THC in it. Correct?
    Dr. Gruber. Correct. Just to clarify, really quick and 
dirty, cannabis sativa-L, the plant, is comprised of hundreds 
of compounds. The primary psychoactive compound is THC. That 
gets you high. The primary non-intoxicating constituent is 
cannabidiol, shown to have tremendous--at least thought to have 
tremendous therapeutic benefit.
    There are many, many other cannabinoids--canabachromine, 
canabajeral, tetrahydro canabaren, as well as terpinoids, the 
essential oils that give cannabis its characteristic scent and 
flavor profile that have also been touted to have potential 
beneficial effects. Flavanoids. The plant is incredibly 
complex. It is not just THC and CBD, although I know that is 
where we start our discussions, but it is important to remember 
that alongside THC we have CBD and other players.
    The Chairman. Would it be possible for Congress to de-
schedule or to treat CBD and other non-THC products differently 
than it would THC or psychoactive components of the plant?
    Dr. Gruber. As I understand it, currently under the 
Controlled Substance Act anything that comes from the plant 
cannabis sativa with greater than .03 percent THC by weight 
falls under Schedule One. Anything that comes from industrial--
so-called ``industrial hemp'' legalized in the 2018 Farm Bill, 
or Hemp Bill, CBD from that source is legal. So that is de-
scheduled.
    The Chairman. So Congress has already carved out an 
exception, basically, for hemp?
    Dr. Gruber. For industrial hemp-derived CBD, ostensibly the 
DEA will allow those types of research studies to move forward.
    The Chairman. And what differentiates those two, is one has 
a negligible, if any, THC component.
    Dr. Gruber. That's right.
    The Chairman. And the other product that is a psychoactive 
one has the THC at a much more concentrated level.
    Dr. Gruber. Much more concentrated levels. Both plants have 
THC. Industrial hemp maxes out by definition as .03 percent THC 
by weight. Cannabis sativa-L, when we think of marijuana, we 
think of that plant that can be bred to have very, very high 
levels of THC, as well as levels of other cannabanoids. There 
are differences in the two cultivars.
    The Chairman. Well that is helpful. Thank you, very much.
    Senator Rosen, do you have anything else you would like to 
ask?
    [No response.]
    The Chairman. Well, let me express my gratitude to each of 
you and our previous panel of witnesses. This is a conversation 
we should have started a long time ago, but I am glad at least 
we are starting it now.
    And as you can tell, there is a lot we have to learn, 
Members of Congress, the policymakers, but I think the American 
people. I think the risks, the health risks of marijuana use 
have been undersold, and as we heard from the previous panel, 
but yet there are beneficial uses that do not involve the 
psychoactive component we have heard that could be enormously 
helpful.
    So this has been very informative and so I thank you for 
it. Thank you for your participation. We are going to close the 
hearing now, but we will leave the record open for another week 
in case any member of the Caucus has written questions they 
would like to ask to follow on.
    But taking Senator Feinstein up on her suggestion, it may 
be that the Caucus would decide to publish a white paper on 
what we have learned here, perhaps for the benefit of others, 
including policymakers like ourselves, and that is something we 
are going to look into as well.
    So we look forward to continuing the conversation with you, 
and thank you very much for being here.
    (Whereupon, at 5:01 p.m., Wednesday, October 23, 2019, the 
hearing in the above-entitled matter was adjourned.)
    [Questions and answers and submissions for the record 
follow.]
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