English Assignment 2

culture of health

with support from:

www.healthaffairs.org/briefs

health policy brief  july 2021

States are adopting policies that expand cannabis access to larger propor- tions of the US population than ever before, as described in an accom-

panying Health Affairs Health Policy Brief. Past-year cannabis use increased from 10.4 percent of US adults in 2002 to 15.3 percent in 2017, and the proportion of past-year users reporting near daily use doubled between 2006 and 2016. During that same period, perceived great risk from smok- ing cannabis declined among those ages twelve and older, going from 38.3 percent in 2002 to 26.1 percent in 2017. It is important to consider whether perceptions about risk are accurate and what may be the larger population health benefits and harms associated with expanded cannabis access.

In this brief, we summarize research on how cannabis legalization relates to use of the substance and key population health outcomes. We focus on recreational laws because of their broad application and ability to affect public health, although we include some studies on medical cannabis laws with generalizable or relevant findings. A detailed summary of representative studies in these domains is provided in supplemental appendix tables 1–7. We conclude by outlining areas ripe for future research and policy consider- ation related to safely legalizing cannabis.

Cannabis Use And Health Research suggests that cannabis use is associated with both positive and negative health effects. The term cannabis refers to parts of or products derived from the plant Cannabis sativa that contain substantial amounts of

Evidence regarding the effects of recreational cannabis legalization on public health is inconsistent. Future research should assess heterogeneous policy design, differential effects on population subgroups, and effects related to characteristics of legal cannabis supply.

CANNABIS LEGALIZATION IN THE US: POPULATION HEALTH IMPACTS

» Research suggests that cannabis use is associated with potential therapeutic benefits but also individual health harms, particularly for adolescent populations.

» Evidence is inconsistent and, in some cases, inconclusive regarding how recreational cannabis legalization affects outcomes significant to public health, including cannabis use, cannabis use disorder, cannabis- related hospitalizations and poisonings, driving safety, and other substance use.

» Researchers can improve on existing evidence by targeting understudied areas, including features of legal cannabis markets, heterogeneous policy effects across populations, and characteristics of cannabis supply such as price, potency, and product type.

» In the face of uncertainty regarding the health consequences of legalization, policy makers should adopt regulatory designs informed by public health priorities and work with researchers to evaluate policy effects.

2health policy brief

culture of health

“Legalization may result in increases in hospitalization and emergency department visits related to cannabis abuse.”

tetrahydrocannabinol (THC)—the substance primar- ily responsible for cannabis’s high-inducing effect. Although it is claimed that cannabis and its derivative substances improve outcomes for many disorders, there is only strong scientific evidence suggesting that it is an effective treatment of three conditions: in treating chronic neuropathic pain in adults, as an anti- emetic after chemotherapy treatment, and for improv- ing patient-reported multiple sclerosis symptoms.

Demonstrated adverse effects of short-term canna- bis use include impaired short-term memory, altered judgement that increases engagement in risky behaviors, and impaired driving. Heavy and long-term cannabis use in adolescents carries substantial risks, including altered brain development and cannabis dependence, which is correlated with elevated risk of using other illegal drugs. Emerging literature suggests that higher-potency cannabis—with a

greater THC concentration—may intensify cognitive impairment, severity of dependence, and adverse psychological outcomes. Although cannabis use has been associated with poor educational outcomes and mental illness, it is challenging to attribute causality to these complex, multifactorial outcomes.

The mechanism of consumption likely affects canna- bis’ health effects. Although large population studies have not identified an association between cannabis smoking and lung cancer, the link cannot yet be ruled out, as cannabis smoke contains carcinogens.

Effects of Cannabis Legalization Evidence is emerging on the public health impacts of cannabis legalization. Here we summarize current research regarding the relationship between rec-

reational and, to a lesser degree, medical cannabis legalization and various outcomes that is key to understanding the public health policy implications. We also highlight three areas ripe for future research: additional measures of cannabis use, use disorder, and product type; heterogenous policy design; and differential effects by population subgroups.

CANNABIS USE Cannabis use is best operationalized through mea- sures of both prevalence (past-month or past-year use) and intensity (for example, number of days used, total grams consumed, potency per dose). Findings on the relationship between recreational legalization and cannabis use among adults are inconclusive, and effects may differ by age group. Using a large, nationally representative survey across several years, two studies observed increased prevalence of past-month cannabis use and frequent use for adults ages twenty-six and older in states with recreation- al legalization but did not report similar changes among young adults ages 18–25. Other research has identified increases in cannabis use prevalence and intensity among college students who fall within the 18–25 age range. Evidence on the impact of legaliza- tion on youth cannabis use remains inconclusive, with research identifying increases, decreases, and no change in use prevalence and intensity measures.

As Rosanna Smart and Rosalie Pacula note, medical cannabis laws, which apply to more limited sectors of the population than do recreational laws, have not been associated with increases in the prevalence of youth (ages younger than eighteen) cannabis use. Al- though these laws appear to correlate with increased use among adults, subgroup analyses suggest that the evidence remains mixed for young adults ages 18–25. Some studies find that medical legalization has no effect on past-month use or use intensity for young adults, although Christine Mauro and col- leagues observed increases in use intensity for males in this age range.

Notably, product characteristics of the legal supply affect the relationship between legalization and can- nabis use and use intensity. Early research describes the evolution of product type, potency, and price after legalization in Washington State. Similar research is needed on the legal medical and recreational markets

3

cannabis legalization in the us: population health impacts

july 2021 | health affairs

“Researchers should... consider the public health effects of...product type, price, potency, and sourcing.”

in other jurisdictions to capture how cannabis market characteristics affect consumption patterns.

CANNABIS USE DISORDER Research on the effects of cannabis legalization on cannabis use disorder is relatively nascent, offering inconclusive findings and suggesting that effects may differ by age group. As Smart and Pacula summarize, medical legalization increases, decreases, or has no effect on self-reported prevalence of or treatment admissions for cannabis use disorder. The few studies that consider heterogenous policy effects of medical cannabis laws suggest that the presence of commer- cial dispensaries increases both overall and youth cannabis use disorder treatment admissions.

This literature is inconclusive partly because the common outcomes used to measure cannabis use disorder—self-reported symptoms or treatment admissions—are likely influenced by legalization without actually changing prevalence of cannabis use disorder. For instance, by changing social norms around problematic cannabis use, legalization may re- duce the likelihood that an individual will self-report symptoms of cannabis use disorder. Similarly, given

that treatment admissions for cannabis use disor- der often occur through the criminal justice system, legalization may affect written and de facto policies governing law enforcement treatment referrals for cannabis use disorder with or without affecting can- nabis use disorder prevalence.

CANNABIS-RELATED HOSPITALIZATIONS AND POISONINGS Cannabis legalization may result in increases in hospitalization and emergency department visits related to cannabis abuse and dependence and inju- ries occurring under the influence of the substance.

A 2020 narrative review reported that cannabis-re- lated hospitalizations in Colorado increased after recreational legalization, above and beyond earlier additions associated with medical legalization. A rigorously designed study found that the presence of recreational cannabis dispensaries, but not enact- ment of a recreational cannabis law, is statistically positively associated with poisonings involving can- nabis dry plant products overall and in those younger than twenty-one. However, because of data limita- tions, this study fails to consider exposures to other cannabis product forms that are of particular concern for youth, such as edibles.

DRIVING SAFETY Potential increases in car accidents involving canna- bis use are a chief concern among those disfavoring legalization. Simulation studies suggest that canna- bis intoxication impairs driver reaction time, spatial perceptions, and decision making. Detection of cannabis in drivers has tripled from 4.2 percent of fa- tally injured drivers in 1999 to 12.2 percent in 2010, although it remains unclear how much of this increase can be attributed to cannabis policy liberalization.

Research investigating the relationship between can- nabis legalization and driving safety typically lever- ages fatal crash data. However, less than 0.5 percent of crashes are fatal, so research using data sets that fail to capture nonfatal injuries underreport traffic accidents associated with driving under the influence of cannabis.

Even among studies that use fatality data and consid- er policy heterogeneity, findings vary from significant positive to significant negative to insignificant rela- tionships between medical cannabis laws and traffic fatalities. Research on recreational cannabis laws is similarly mixed, likely as a result of methodological differences and confounding variables.

USE OF OTHER SUBSTANCES The extent to which cannabis interacts with other substances heavily influences the public health impli- cations of legalization. In particular, whether cannabis is a complement or substitute to alcohol, tobacco, or opioids is a critical consideration for legalization pol- icy. The effect of legalization on substance use likely differs by substance and user age.

4health policy brief

culture of health

“There has been a proliferation of high- potency products in legal cannabis markets.”

Overall, the literature on the effects of cannabis laws on alcohol use remains mixed for both adolescents and adults, suggesting both substitution and comple- mentary relationships. Studies of recreational can- nabis laws have identified both significant declines and insignificant effects on alcohol use with cannabis and without cannabis, as well as intensity of alcohol use. The emerging literature on tobacco is similarly inconclusive but has begun to assess differential effects of legalization across tobacco products. For example, Rebekah Coley and colleagues find that recreational legalization increases e-cigarette use

among adolescents but has no effect on cigarette use. Early evidence on medical cannabis laws suggests that the complementary or substitutive nature of the relationship between alcohol or tobacco and cannabis depends on policy restrictiveness and the age of the consuming population.

Research has also focused on the potential for cannabis legalization to address opioid-related harms. A growing minority of states recognize opioid dependence as a qualifying condition for medical cannabis access. Although older studies identified a negative association between medical cannabis laws and opioid mortality, subsequent replications using additional data years have suggested that omitted variable bias may have driven earlier findings. More recent research highlights the importance of consid- ering policy dimensions in evaluations of legalization policies. For example, the existence of dispensaries in medical or recreational legal markets, not legal- ization alone, may contribute to any observed effect on opioid mortality. Although researchers find (with important exceptions) that opioid prescribing is neg- atively associated with medical legalization or certain features of medical cannabis markets, this literature may inadequately control for changes in public and private policies and programs targeting opioid misuse.

For more detailed information about legalization and

noncannabis substance use, we refer readers to re- views from Gabrielle Campbell and colleagues, Smart and Pacula, and Meenakshi Subbaraman.

Future Research Directions Although more research is needed regarding the pub- lic health consequences of a legal cannabis supply for adults, we have elucidated what is known about four key health outcomes: cannabis use and use disorder, cannabis-related hospitalizations and poisonings, driving safety, and other substance use. Expansion of cannabis research into understudied areas may help address some of the existing inconsistent evidence.

For instance, future research should evaluate specific provisions that govern the legal market. Features of medical and recreational cannabis laws, such as whether a jurisdiction allows dispensaries, likely affect health outcomes and explain discrepancies be- tween studies that do not stratify states by relevant provisions. Although some studies assess the effect of recreational dispensaries on cannabis use, uninten- tional cannabis exposure, motor vehicle fatalities, and opioid mortality, differentiating states by provisions is not as common in recreational legalization research compared with the more established literature on medical cannabis laws. Further, many studies only evaluate provisions related to legal supply methods (for example, dispensaries, home cultivation), ignoring other elements of the regulatory framework that may have significant implications for public health out- comes. These include provisions such as taxation and advertising restrictions. Evaluations of provisions that govern legal markets could benefit from a cate- gorization system that differentiates states on the basis of multiple characteristics. In addition, analyses should distinguish between policy implementation and effective dates.

Researchers should also consider the public health effects of different characteristics of the legal can- nabis supply, including product type, price, potency, and sourcing. Cannabis legalization, particularly commercialization, has the potential to transform the cannabis market. For instance, there has been a prolif- eration of high-potency products in legal cannabis markets, both in the US and abroad. Novel extracts also make up a rapidly growing market segment.

5

cannabis legalization in the us: population health impacts

july 2021 | health affairs

“Legalization has the potential to create or exacerbate socioeconomic and health inequities.”

Given public perceptions that alternatives to smoked cannabis products are healthier and more efficient to consume, it is critical to assess their public health effects. Use will also be shaped by the post-tax retail price, and as anticipated, cannabis prices have fallen steeply in states that have legalized recreational use. Thus, researchers should prioritize evaluating the ef- fects of different taxation approaches (for example, ad valorem or based on THC content) on use.

Further, the 2020 vaping crisis associated with dilut- ed THC-containing products raises concerns around unregulated cannabis markets in both legalized and nonlegalized states, heightening the need to study the public health effects of legally versus illegally produced cannabis products. Notably, cannabis mar- kets vary at the local level, and the cannabis industry will continue to evolve in response to federal and state policy changes. Thus, establishing data systems capable of capturing local characteristics of cannabis markets over time will be essential.

It is also critical that researchers expand the study of heterogeneous policy effects across population groups. Our review highlights several studies that evaluate differential effects by age. Researchers should also build on the notable research studying effects by race and ethnicity to investigate why le- galization may exert differential effects on cannabis

and other substance use for different populations. Cannabis legalization is promoted as a tool to ad- vance social equity, yet legalization has the potential to create or exacerbate socioeconomic and health inequities. Having a criminal record has implications both for health and for economic well-being. Although declines in adult arrests follow cannabis legalization, racial disparities in arrest rates persist, and more research is needed on how the financial and remaining criminal penalties for cannabis violations are distrib- uted across demographic groups. Whether health and

other harms associated with cannabis- related criminal justice contact continue to be con- centrated among racial and ethnic minorities after legalization deserves careful study.

Beyond criminal justice contact, the design of canna- bis markets has health equity implications. Low-in- come and racial/ethnic minority communities, as well as youth, are especially vulnerable to the commer- cialization of cannabis. For instance there is some evidence that cannabis dispensaries are concen- trating in minority communities. Researchers should prioritize an examination of the differential impact of attributes of legalized markets—including taxation mechanisms, location of cannabis outlets, marketing strategies, product design, and potency— by social class, race, ethnicity, and age. Further, recent controversies over the effectiveness of social equity provisions embedded within cannabis policy reform call for researchers to evaluate whether these initia- tives are achieving their intended effects or produc- ing new inequities.

Even if researchers fill these gaps in the literature, data and methodological challenges limit our ability to draw conclusions about other impacts of legaliza- tion. For instance, research could be strengthened by adoption of a clear, consistent, and expansive defini- tion of cannabis “use” across data sources. As Beau Kilmer and Rosalie Pacula highlight, research must move beyond measures of prevalence to include mea- sures of use intensity, such as days used, total grams consumed, and potency per dose. Although research- ers should work to develop standardized definitions for and methods to collect dosage information that is comparable across products, it is important to acknowledge that these measurement improvements may add significant costs to study designs and must be weighed against feasibility.

Another important area for methodological and data improvements is in understanding how cannabis legalization relates to driving safety. There exist challenges to reliably measuring THC impairment in drivers (for example, in blood), and uncertainty remains over what level of THC in the blood leads to impairment. In addition, future research should clarify how alcohol and cannabis co-use affects driving impairment. Improved data sources that include in-

health policy brief

culture of health

This Health Policy Brief was produced with the generous support of the Robert Wood Johnson Foundation. All briefs go through peer review before publication.

Written by Rebecca Haffajee, acting assistant secretary for planning and evaluation and principal deputy assistant secretary for planning and evaluation at the Department of Health and Human Services, in Washington, D.C., and former policy researcher at the RAND Corporation, in Boston, Massachusetts, and assistant professor of health management and policy at the University of Michigan School of Public Health, in Ann Arbor; and Amanda Mauri, a PhD candidate at the University of Michigan in the Department of Political Science and the Department of Health Management and Policy, in Ann Arbor. This article was conceived and drafted when Haffajee was employed at the RAND Corporation, and the findings and views in this article do not necessarily reflect the official views or policy of her current employer, the US Department of Health and Human Services, nor the US government.

Cite as: “Cannabis Legalization In The US: Population Health Impacts,” Health Affairs Health Policy Brief, July 1, 2021. DOI: 10.1377/hpb20210701.500845

7500 Old Georgetown Road, Suite 600 | Bethesda, Maryland 20814-6133 USA | © 2021 Project HOPE—The People-to-People Health Foundation, Inc.

6

“There is some evidence that cannabis dispensaries are concentrating in minority communities.”

formation on crashes and fatalities by substance type are essential to fully assessing the impact of legaliza- tion on driving safety.

Policy Implications As policy makers design or revise legal markets, it is important to note that research on early recreational legalization adopters may not be generalizable to all states and localities. The states subject to the most

research so far (Colorado, Oregon, and Washington) all had expansive medical programs established before recreational legalization and mostly adopted commercial approaches toward the recreational

market. It is unclear whether states with less com- mercialized medical programs or that adopt different supply chain architectures for recreational supply will experience similar effects on use and public health outcomes.

Nevertheless, there are opportunities for policy makers to incorporate a public health perspective in the design of legal cannabis markets. These include suggestions based on lessons learned from tobacco and alcohol policy and recommendations that focus on youth cannabis use. Other important policy goals may include minimizing drugged driving, unwanted contaminants, and co-substance use. Policy makers may also consider adopting alternative legalization models beyond commercial markets and should thoughtfully incorporate social equity considerations into legalization design and oversight through provi- sions that address socioeconomic and health dispari- ties. Finally, policy makers should work with research- ers to evaluate the impacts of their own legalization schemes as they unfold.