HomeMy WebLinkAbout2017-10-26 Board of Health Supplemental Materials (2) i
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Monitonng
Health
Related to Manjuana
in Coloradoe. 2016I
Changes in Marijuana Use Patterns,
Systematic Literature Review,
and Possible Marijuana-Related
Health Effects
Ah
COLORADO
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Department of public
Health&Environment
colorado,gov/cdphe/marij uana-health-report
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Presented to the Colorado State Board of Health, the Colorado
OeD8F[U0eOt of Revenue, and the [-OinradC) General Assembly on Monday,
|aDU2l[V 70, 7017 by the Retail Marijuana Public Health Advisory
rn[DDO'[tee pursuant tO25-1 ,5-11M/ C.R.S.
This [eOO[f has been reviewed by Larry k@D/ kNSPA, Executive
Director and [-h`pf Medical Officer, /-Oi«rmd0 Department of Public AeaH'k
and Environment
Retail Marijuana Public Health Advisory A ��� �� � � Committee
The Retail Marijuana Public Health Advisory Committee was established per Senate Bill 13'283and 25-
1.5-118, C.R.S. Duties of the Committee are to review the currently available scientific literature and
data on health effects ufmarijuana use and data on patterns ofmarijuana use, on an ongoing basis.
This document summarizes health topics and data reviewed beginning in 2014 with updates conducted
through 2016, As committee, wragree that reported findings reflect current science. Public health
messages were developed by the committee to accurately communicate scientific findings.
Recommendations repo/ted were developed by the committee with the goal of protecting consumers of
marijuana and the general public,
25-1 .5~1 10/ C.R.S. Monitor health effects of marijuana
''The department shalt monitor changes in drug use patterns, broken down bvcounty and race and
ethnicity, and the emerging science and medical information relevant tuthe health effects associated
with marijuana use. The department shalt appoint a panel ofhealth care professionals with expertise
in cannabinoid physiology to monitor the relevant information. The panel shalt provide a report by
January 31, 2015` and every two years thereafter tothe state Board ofHealth, the Department of
Revenue' and the General Assembly. The department shalt make the report available on its web site.
The panel shalt establish criteria for studies to be reviewed' reviewing studies and other data, and
making recommendations, as appropriate, for policies intended to protect consumers ofmarijuana or
marijuana products and the general public. The department may collect Colorado-specific data that
reports adverse health events involving marijuana use from the aK'payerclaims database, hospital
discharge data, and behavioral risk fnctors."
HISTORY: Source: L. 2013: Entire section added, / effective
May 28.L. 2016: Entire section amended, , effective August 10.
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Monitodng Health Concerns
a 19 0
Related to Manjuana in
Colorado: 2016
Table of Contents
—E�ecutiWve Summar y x
Background and Summary of Key Findings 2 - 6
Behavioral Risk Factor Surveillance Survey (BRFSS) 7 - 2-6
Child Health Survey (CHS) 27 - 36
Healthy—Kids Colorado Survey (HKCS) 37 - 60
Pregnancy—Risk Assessment—Monit-o-r-ing System (PRAMS) 61 - 70
Background and Summary of Key Findings 72 - 80
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81 - 92
System—atic Literature Review Process
Marijuana Use Among Adolescents and Young Adults 93 - 108
Marijuana Use and Cancer 109 - 118
Marijuana Use and Cardiovascular Effects 119 - 126
Marijuana Dose and Drug Interactions 127 -- 144
Marijuana Use and Driving —----- 1145
Marijuana Use and Gastrointestinal and Reproductive Effects 157 - 164
Marijuana Use and Injury 165 - 178
Marijuana Use and Neurological, Cognitive and Mental Health Effects 179 - 192
Marijuana Use During Pregnancy and Breastfeeding 193 - 208
Marijuana Use and Respiratory Effects 209 - 220
Unintentional Marijuana Exposures in Children 221
Big
Background and Summary of Key Findings 230----- 234
Rocky Mountain Poison and Drug Center (RMPDC) Data 235 - 246
---Colorado Hospital Association-(CHA) Data 247 - 270
Retail Marijuana Public Health Advisory Committee 2015-2016 Membership 271 278
Roster
Glossary 279 286 ^
ACOLORADO
V.P.d -t.Mbft
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Monitoring Health
Concerns Related to
in
Marijuana
Colorado : 2016
Executive Summary
Retail Marijuana Public Health Advisory
Committee
COLORADO
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Introduction
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When Colorado became one of the first two states in the nation to legalize retail marijuana, the
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Colorado LegistatUre mandated that the Colorado Department of Public Health and Environment
� ([DPHE) study the potential public health effects ofmarijuana. Though medical marijuana has been
legal in Colorado since 2000' it was largely viewed as an individual doctor/patient decision outside the
scope ofpublic health policy. However, the legalization of retail (non-mmdicaQ marijuana and the
potential for greater availability ofmarijuanoin the community prompted o closer look at potential
health effects onthe population atlarge.
Legalized retail marijuana presents aparadigm shift, grouping marijuana with other legal substances
like alcohol, tobacco and prescription drugs' asopposed tnillicit drugs like cocaine and heroin. As with
alcohol, tobacco and prescription drugs, misuse ofmarijuana can have serious health consequences.
The standard public health approaches toalcohol, tobacco and prescription drugs are to monitor use
patterns and behaviors, health care use, potential health effects, and emerging scientific literature to
guide the development of policies or consumer education strategies to prevent serious health
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consequences. This report presents information on marijuana use patterns, potential health effects and
the most recent scientific findings associated with marijuana use, with a key objective of helping
facilitate evidence-based policy decisions and science-based public education campaigns.
In 25-1.5-1 10, C.R.S., the Colorado Department of Public Health and Environment (CDPHE) was given
statutory responsibility to:
monitor changes in drug use patterns, broken down by county and race and ethnicity, and the
emerging science and medical information relevant to the health effects associated with marijuana
use.
°
appoint a panel of health care professionals with expertise in cannabinoid physiology to monitor
the relevant information."
cnUec1Colorado-specific data that reports adverse health events involving marijuana use from
the aK'payerciaims database, hospital discharge data, and behavioral risk factors."
Based on this charge, [DPHE has appointed a 14-member committee, the Retail Marijuana Public
Health Advisory Committee (0MPHAC), to review scientific literature on the health effects of marijuana
and Colorado-specific health outcome and use pattern data. Members of this committee (see Retail
Marijuana Public Health Advisory Committee membership roster) consist of individuals in the fields o/
public health, medicine' epidemiology and medical toxicology who demonstrate expertise related to
marijuana through their work, training or research. This committee was charged with the duties as
outlined in C.R.S. 25-1.5-110 to '^... establish criteria for studies kobereviewed, reviewing studies and
other data, and making recommendations, as appropriate, for policies intended to protect consumers
of marijuana or marijuana products and the general public." The committee began meeting in May
2014 and in January 2015 published the first edition of this report. The overall goat of the committee
was to implement an unbiased and transparent process for evaluating scientific literature as well as
marijuana use and health outcome data. The committee was particularly interested in ensuring quality
information is shared about the known physical and mental health effects associated with marijuana
use and also about what is unknown at present. The official committee bylaws are included in the
Appendix` Retail Marijuana Public Health Advisory Committee Bylaws.
......... -_-_--
COLOR4DO
Monitoring Health Concerns Related mMarijuana|nColorado: ao1^ Department of Publicm
Health*^nviro"°,",
Executive Summary
Monitoring �� an� ^��� 0 marijuana W�� patterns
This report includes detailed information about marijuana use patterns in Colorado that has been
gathered using several prominent population-based surveys. These surveys are:
Y. The Behavioral Risk Factor Surveillance System survey, a survey of adults sponsored by the U.S,
Centers for Disease Control and Prevention (CDC).
l The Child Health Survey' a survey of adults with children ages 1-14years old in their home about
the children's health and environment.
]. The Healthy Kids Colorado Survey of middle and high school students, a collaboration of CDPHE,
Colorado Department ofEducation, and Colorado Department of Human Services.
4. The Pregnancy Risk Assessment Monitoring System survey, a survey of women who recently gave
birth.
The data available at this time cannot answer all ofthe important questions about whether orhow
marijuana use patterns may be changing as a result of legalization. However, they do provide
important insights into marijuana use in adults and vulnerable populations such as pregnant women,
youth, and those with racial, ethnic, and sexual orientation disparities. Asummary of key trends:
Encouraging trends
° For adults and adolescents, past-month marijuana use has not changed since legalization either in
terms ofthe number ofpeople using orthe frequency ofuse among users.
• Based onthe most comprehensive data available, past month marijuana use among Colorado
adolescents isnearly identical tothe national average.
° We have not identified any new disparities in marijuana use by age' gender' race, ethnicity or
Sexual orientation since iegaUzation.
° Daily or near-daity marijuana use among adults is much tower than daily or near-daiLy alcohol or
tobacco use. Among adpiescenis, past month marijuana use is lower than past month alcohol use.
Trends to continue monitoring
° About 6 percent ofpregnant women use marijuana white pregnant. This percentage is higher
among those with unintended pregnancies as well as younger mothers or those with less education.
° AL [east 14,000 children in Colorado are atrisk ofaccidentally eating marijuana products that are
not safety stored and at least 16'000are at risk ofbeing exposed tusecondhand marijuana smoke
inthe home,
° More than 5 percent of high school students use marijuana daily ornear daily. This rate hos
remained stable since at [east 2005.
w Past month marijuana use among adults inColorado is higher than the national average. in
Colorado, one in four adults age 18-25 reported past month marijuana use and one in eight use
daily or nemr'daiiy. These numbers have been consistent since legalization.
° There continue to be disparities in marijuana use based on race/ethnicity for adolescents and
sexual orientation for both adults and adolescents.
v White past month marijuana use among adults and adolescents was stable for most regions in
Colorado, adult use in the Northwest Colorado region increased from 2014 to 2015.
* Munethan1'in'3adoiescentsvvhmusemerijumnafi/stusmithya8e14, suppordnyprevendon
efforts aimed at children before they enter ninth grade.
COLORADO
Monitoring xeuithConcerns nemtedtoMarijuana mColorado: zo|+ A Health b Environment
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Executive SUrnmary
Scientific literature reviewoDpotential health effects
mfmarijuana Use
The committee used a standardized systematic literature review process to search and grade the
existing scientific literature on health effects of marijuana. Findings were synthesized into evidence
statements that summarize the quantity and quality of supporting scientific evidence. These evidence
statements were classified as follows:
° Substantial evidence - indicates robust scientific findings that support an association between
marijoanause and the outcome.
* Moderate evidence - indicates that scientific findings support an association between marijuana
use and the outcome, but these findings have some limitations.
^ Limited evidence - indicates mudestscientific findingsthat Support nn association between
marijuana use and the Outcome, but these findings have significant Limitations.
^ Mixed evidence - indicates both supporting and non-supporting scientific findings for an association
between marijuana use and the Outcome with neither direction dominating.
" Body of research failing to show un association - indicates that the topic has been researched
without evidence of an association; is further classified as a limited, moderate mrsubstantial body
of research.
m Insufficient evidence ' indicates that the outcome has not been sufficiently studied to conclude
whether or not there is an association between marijuana use and the outcome.
The committee also translated these evidence statements into plain language so the public can
understand them when used in public health messages. In addition, the committee was asked to
develop public health recommendations based uupotential concerns identified through the review
process and to articulate research gaps based on common limitations of existing research. All ofthese
were presented to the full committee during open public meetings that offered opportunities for
stakeholder input. Final statements' recommendations, and research gaps were formally approved by a
majority vote of the committee.
An important note for all key findings is that the available research evaluated the association between
marijuana use and potential adverse health outcomes. This association docs not prove the marijuana
use alone caused the effect. Despite the best efforts ofresearchers ieaccount for confounding
hyc&on' there may be other important factors related tocausality that were not identified. In
addition, marijuana use was illegal everywhere inthe United States prior tu1996. Research funding,
when appropriated, was commonly sought toidentify adverse effects from marijuana use. This legal
fact introduces both funding, bias and publication bias into the body ofLiterature related to marijuana
use. Another[imitation of the available research data is that most studies did not or could not measure
the THC Level (potency) of marijuana used by subjects, nor which other cannabinoids were present.
There are diverse products now available in Co(orado, many ofwhich are Likely higher in potency than
the marijuana used bystudy subjects for much of the literature reviewed.
The Retail Marijuana Public Health Advisory Committee recognizes the limitations and biases inherent
in the published literature and made efforts toensure the information reviewed and synthesized is
reflective of the current state of medical knowledge. Where information was tacking for whatever
reason the committee identified this knowledge gap and recommended further research. This
information vviKheupdated as new research becomes available.
COLORADO
Executive Summary
Ma ~Vana use among adolescents and young adults
The committee reviewed the relationships between adolescent and young adult marijuana use and
cognitive abilities, academic performance, mental health and future substance use. Weekly marijuana
use byadolescents is associated with impaired learning, memory, math and reading, even 28 days after
iayL use. Weekly use iyalso associated with failure Lo graduate from high school. Adolescents and young
adults who use marijuana are more likely to experience psychotic symptoms as adults, such as
hallucinations, paranoia, delusional beliefs and feeling emotionally unresponsive. Evidence shows that
marijuana users can become addicted to marijuana and that treatment for marijuana addiction can
decrease use and dependence, Additionally, marijuana users who quit have lower risks ofcognitive and
mental health outcomes than those who continue to use.
Marijuana use and cancer
The committee reviewed different forms of cancer relative to marijuana use, as welt as the chemicals
released in marijuana smoke and vapor. Strong evidence shows that marijuana smoke contains many of
the same cancer-causing chemicals found in tobacco smoke. However, there isconflicting research for
whether or not a higher cumulative level of marijuana smoking is associated with lung cancer. Limited
evidence suggests an association between marijuana use and both testicu(nrand prostate cancem. On
the other hand, the limited evidence available concerning cancers of the bladder, head and neck
suggests that they might not have any association with marijuana use.
Marijuana use and cardiovascular effects
The committee reviewed myocardia( infarction' stroke and death from cardiovascular causes, relative
to marijuana use. There is amoderotm level ufscientific evidence that marijuana use increases risk for
some forms ofstroke in individuals younger than 55 years of age, and more limited evidence that
marijuana use may increase risk for heart attack. Research is tacking concerning other cardiovascular
events and conditions, including death.
Marijuana dose and drug interactions
The committee reviewed THC (tetra hydnocannmbinot, the main psychoactive component of marijuana)
levels relative to marijuana dose and method of use, the effects of secondhand marijuana smoke, drug-
drug interactions involving
rug'drugintermctimnminvoiving marijuana, and relationships between marijuana and opioid use. One very
important finding isthat 1tcan take uptofour hours after consum1nganedible marijuana product to
reach the peak THC blood concentration and fee( the full effects. There is credible evidence of
clinically important dru8'druginterucdons between mahjuana and multiple medications, including
some anti-seizure medications and a common biood'th1nner. Data about potential interactions are
tacking for many drugs at this time and likely to evolve subxLanUaKyover coming years. Finally, there
is some evidence that opioid pain medication overdose deaths are tower in states with legal medical
marijuana than would be expected based on trends in states without legal medical mahjuana. There is
conflicting evidence for whether or not marijuana use is associated with m decrease in opioid use
among chronic pain patients orindividuals with a history of problem drug use.
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COLORADO
Monitoring HeakhConcerns ReiatcdmMarijuana/nCu(madv: IO16 |Department of rmw* v|
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Executive Summary
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MarijuanaUse and driving
The committee reviewed driving impairment and motmrvehicle crash risk relative to marijuana use, as
well as evidence indicating how long ittakes for impairment to resolve aftermarijuana use. They
found that the risk of a motor vehicle crash increases among drivers with recent marijuana use.
Furthermore, the higher the blood THC level, the higher the moLurvehic\e crush risk. In addition, using
alcohol and marijuana together increases impairment and the risk of n motor vehicle crash more than
using either substance alone. For less than weekly marijuana users, using marijuana containing 10
milligrams or more nfTHC is likely toimpair the ability to safety drive, hike' or perform other safety-
sensitive activities. Less than weekly users should wait at least six hours after smoking or eight hours
after eating or drinking marijuana to allow time for impairment to resolve.
Marijuana Use and gastrointestinal or reproductive effects
The committee reviewed gastrointestinal diseases, particularly cyclic vomiting, and infertility or
abnormal reproductive function. Evidence shows that iong'time, daily or near daily marijuana use is
associated with cyclic vomiting, which has been called cannabinoid hyperemesis syndrome. in such
cases` stopping marijuana use may relieve thevomiLing. There is conflicting research for whether or
not marijuana use bassociated with mate infertility urabnormal reproductive function, and research is
lacking oofemale reproductive function related tomarijuana use.
Marijuana use and injury
The committee reviewed workplace, recreational and uthernon'driving injuries' burns from hash-oil
extraction or failed electronic smoking devices' and physical dating violence, Evidence shows that
marijuana use may increase the risk of workplace injury white impaired, but is unclear for other types
ufnon-driving related injury. There have been many reports of severe burns resulting from home-
extraction of butane hash-oil Leading to explosions, and cases of electronic smoking devices exploding,
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leading totrauma and burns. Concerning dating violence, adolescent girls who use marijuana may be
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more likely bucommit physical violence against their dating partners, and adolescent boys who use
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marl juana may bemore likely to bevictims ofphysical dating violence,
Marijuana use and neurological, cognitive and mental health effects
The committee reviewed the potential relationships between marijuana use and cognitive impairment,
mental health disorders and substance abuse. Strong evidence shows that daily ornear daily marijuana
users are more Likely to have impaired memory lasting aweek ormore after quitting, An important
acute effect of THC in psychotic symptoms, ouch as hallucinations, paranoia and delusional beliefs
during intoxication. These symptoms are worse with higher doses. Daily ornear daily marijuana use is
associated with developing a psychotic disorder such as schizophrenia. Finally, evidence shows that
marijuana users can become addicted to marijuana and that treatment for marijuana addiction can
decrease use and dependence.
Marijuana use during pregnancy and breastfeeding
The committee reviewed adverse birth outcomes, effects of prenatal marijuana use on exposed
offspring later in childhood or adolescence and effects of marijuana use by o breastfeeding mother.
8iohgica} evidence shows that THC passes through the placenta to the fetus' so that the unborn child
is exposed to THC if the mother uses marijuana, and that THC passes through breast milk to a
breastfeeding child. Marijuana use during pregnancy may be associated with an increased risk ofheart
defects orstiUbirth. Stronger evidence was found for effects that are seen months or years after birth
ifachild's mother used marijuana white pregnant with the child. These include decreased growth and
impaired cognitive function and attention. Decreased academic ability urincreased depression
symptoms may also occur.
COLORADO
Monitoring Hmk»Concerns xciatedmMarijuana incoiomuo: z01a Department of Public w|
Summaiy
Marijuana use and respiratory effects
The committee reviewed respiratory diseases like chronic obstructive pulmonary disorder (COPD),
chronic bronchitis and asthma, respiratory infections and lung function relative to smoked marijuana
They also reviewed potential health effects of vaporized marijuana. Strong evidence shows an '
association between daily or near-daity marijuana use and chronic bronchitis. Additionally, daily or
near daily marijuana use may be associated with bLI11OUS lung disease and pneumothorax in individuals
younger than 48years ofage. Research islacking concerning any possible association between
marijuana use and COPD, emphysema orrespiratory infections. Smokers who switch from manjuona
smoking to marijuana vaporizing may have fewer respiratory symptoms and improved pulmonary
function. Finally, u notable effect ofacute use isa short-term improvement in lung airflow.
Unintentional marijuana exposures inchildren
The committee reviewed unintentional marijuana exposure relative to marijuana legalization and
child-resistant packa8in8. They found strong evidence that more unintentional marijuana exposures of
children occur in states with increased legal access to marijuana, and that the exposures can lead to
significant clinical effects requiring hnspitaUzaUon. Additionally, evidence shows that child resistant
packaging prevents exposure to children from potentially harmful substances, such as THC.
Monitoring possible marijuana-related health effects
This report includes detailed information about population-based health effects of tegatized marijuana
in Colorado, using two primary public health datasets:
1. Exposure calls to the Rocky Mountain Poison and Drug [enter, typically used as a surrogate data
source tudetermine the potential for adverse health effects from exposure tochenn1cais and drugs.
2. Hospital and emergency department data provided by the Colorado Hospital Association, which
collects data from participating hospitals in the state of Colorado.
The data presented here provide important insights into the yearly volume, trends over time and
nature ofmarijuana exposure calls tothe poison center among different age groups and the rates of
hospitalizations and emergencydepa/tment visits for which a marijuana-reioted billing code was used.
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Encouraging trends
° Marijuana exposure calls to the poison center appear to be decreasing since 2015' including
unintentional exposures in children ages O'8years.
° The overaK nate of emergency department visits with marijuana-reiated bitting codes dropped 27
percent from ZUl4io2O1S (2Ui6data isnot available ye¢
Trends tQcontinue monitoring
• Marijuana exposure calls to the poison center continue to be higher in years after medicat
marijuana commercialization (ZO10-2O16) than in previous years (2000'2009), including calls about
children O'Dyears old with unintentional marijuana exposure,
° Edible marijuana products were involved in about 40 percent of marijuana exposure calls to the
poison center. For children 0-8 years old, calls about edible marijuana were twice as common as
calls about smokeable marijuana.
° The overall rate ofhospitalizations with marijuana'reiatcd bitting codes hos increased each year
since 2008.
Monitoring xeu<,hcvncem �
snciadm`wa,U �
Marijuana in COLOR4D#Department of Public vm
A If=`°"li°monm"",
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Executive Surnmary
" Among young adults (ages 18-2Syears) in2014and 2015' about D percent ofall hospitalizations and
2 percent ofat[ emergency department visits had m marijuana-related bitting code. This was higher
than the rate among other age groups, and likely reflects the higher rate mfmarijuana use inthis �
age group. �
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Disparities in hospitalizations and emergency department visits also existed by sex and race, with
higher rates among mates and blacks across all time periods.
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Hospitalizations with mzhjuana'reiated billing codes are nine times more likely to have primary
mentat health diagnosis compared to those without ma rij uana-related billing codes.
These data should be interpreted carefully, keeping in mind that observed increases have many
potential explanations including: changes in the amount or type of marijuana use in Colorado,
changes in physician screening orreporting related to marijuana, increased honesty in reporting
marijuana use to health cane providers after legalization, and changes in coding practices by hospitals
and emergency departments. In addition, possible marijuana-related cases accounted for 3percent of
hospitalizations and less than i percent ofemergency department visits inColorado in2O15. More data
and time are needed to determine if the observed increases are a direct and sustained result of
changes inColorado marijuana use.
Public health recommendations
The committee made a number of public health recommend ations interspersed throughout this report.
It recommends Colorado support research tofill important gaps in public health knowledge and
continue improving and standardizing data about marijuana use history and health effects in pubhc
health surveillance, medical care settings and research.
Collection and in-depth analysis of data regarding marijuana use should be continued using population-
baseduurve}wxuch as the Behavioral Risk Factors Surveillance 5ystem' the Healthy Kids Colorado
Survey and Pregnancy Risk Assessment Monitoring System. Colorado also should continue to develop,
improve and expand toots to monitor morijunnause patterns, such as [DPHE'sCannabis Users' Survey
on Health.
[DPHEshouid continue using poison center and hospital data to monitor trends in potential marijuana
health effects and assess the impact overtime, especially among groups With higher rates of marijuana
use. For the poison center, this includes implementing a surveillance protocol currently being
developed and conducting more detailed data collection and analysis of unintentional marijuana
exposures, especially in children under years old. In order to better assess potential health impacts,
data on hospitalizations and emergency department visits related to marijuana should be further
explored. This includes continuing analysis ofprimary diagnoses in relation to marijuana-related billing
codes and targeted projects Like COPHE'scollaboration toevaluate ski-related injuries and marijuana.
In addition, improved testing methods and documentation are needed in relation to motor vehicle
crashes and driving under the influence of drugs (UU|D). Evaluation of death certificate and coroner's
report data should continue, to determine how it can best be used in monitoring for potential
marijuxma'reiateddeaLhs.
Public education on potential health effects ufmarijuana is important, particularly related tothe
effects ofuse during pregnancy, adolescent use, driving after using and unsafe storage around
children. Dispensaries and industry should continue to partner with public health to disseminate
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education about these topics of highest concern. Education for health care providers on the known
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health effects of marijuana use may encourage more open dialogue between providers and patients.
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COLORADO
Executive Summary
Research gaps
Important research gaps related to the population-based health effects of marijuana use were
identified during the literature and data review process. These research gaps were based on common
(imitations of existing research' exposures or outcomes not sufficiently studied, or issues important to
public education or policymaking. These research gaps provide an important framework for continuing
toprioritize research related tomarijuana use and public health. The committee strongly recommends
that Colorado support research to fit( these important gaps in public health knowledge. While outside
the scope ofthis committee's duties, the committee also recognizesthat more reseanhisneeded un
the potential therapeutic benefits ofmarijuana.
4common theme among the research gaps was the need for studies with better defined marijuana-use
histories and practices. This should include frequency, amount, potency, and method of marijuana use,
(ength of abstinence, and a standardized method for documenting cumulative lifetime marijuana
exposure. A key need is to separately evaluate effects for less frequent users versus daily ornear-daiiy
users. Researchers should consider evaluating separately byage group, sax nrother characteristics
when the health effect being studied couid differ among groups ' for example, by age for
cardiovascular effects or by sex for menta[ health effects.
Research gaps particularly important to public health and safety include: 1) Additional research using
marijuana with THC levels consistent with currently available products; 2) Research on impairment in
marijuana users who use more than weekly and may have developed tolerance; 3) Research to identify
improved testing methods for impairment either through alternate biological testing methods or
physical tests of impairment; and 4) Research to better characterize the
pharmacokinetics/pharmacodynamics, potential drug interactions, health effects, and impairment
related to newer methods ofmarijuana use such aaedibles and vaporizing aswell asother
cannabinoids such as cannabidiol ([8D).
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