Policy Studies Harm Reduction

Cannabis Is Not Risk Free, but Smart Policies Can Reduce Harm


Stacey McKenna
Resident Senior Fellow, Integrated Harm Reduction
Chelsea Boyd
Resident Research Fellow, Harm Reduction

Key Points

Concerns raised by campaigns and groups opposing cannabis legalization often contain some truth but present an incomplete, misleading picture about the effects of cannabis. This occurs because the messages assume causation when evidence only suggests association or because the degree of complexity in understanding an issue is not explored. 

Cannabis consumption is not without risks, but most people engage in a variety of behaviors that pose a risk to their health on a regular basis, from driving a car to drinking alcohol.

Risks associated with cannabis use can be effectively diminished through targeted policy and a well-regulated marketplace. 

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Executive Summary

Since California legalized medical cannabis almost three decades ago, support for relaxed laws around the Schedule I substance has spread throughout the United States. More than three-fourths of states permit medical use, and more than one-third have legalized recreational adult consumption. As 91 percent of U.S. adults now support some degree of regulated legalization and politicians on both sides of the aisle are seeking federal decriminalization, this legislative trend is likely to continue.

Nonetheless, a number of national and community groups continue to speak out against cannabis legalization, voicing concerns about public health and safety. In this paper, we analyzed eight anti-cannabis efforts to identify several salient public health-related fears, assessed the validity of those claims and considered relevant implications for policy.

Our analysis of state and national efforts against cannabis legalization revealed five priority concerns: rising tetrahydrocannabinol (THC) levels; the connection between cannabis use and mental health conditions; youth consumption; accidental poisonings, particularly among children; and the effect of cannabis intoxication on driving. In-depth reviews of the literature around each of these concerns showed that the issues tend to be highly nuanced. THC levels do appear to be higher than in the past, but this may be due to consumer preferences and market pressures, not exclusively or even primarily due to legalization. Cannabis consumption is linked to several mental health issues, but evidence on causal connections remains absent for some conditions and inconclusive for others. Legalizing cannabis for either medical or recreational adult consumption has not had any significant effect on past-30-day use among teens. Increased access to certain products that are more common in illicit markets—such as edibles—may be driving an increase in accidental consumption among children, but the overall numbers remain extremely low. And while THC likely does cause some driving impairment in most people, the extent of that impairment varies drastically from one person to another and is very difficult to assess.

These findings suggest that although cannabis is not risk free, most negative consequences can be mitigated through smart policy. As such, given the continuing trend toward legalization in the United States, we recommend several ways that federal, state and local entities can support harm-reducing approaches that will protect both consumer safety and autonomy across the country’s discrete regulated cannabis markets.

Our policy recommendations include federal standards for and state regulation of dosing, potency and labeling; increased research and support for pilot programs to develop evidence-based strategies to assess cannabis-impaired driving; and continued support for youth-prevention efforts such as age minimums, compliance checks and targeted, fact-based prevention media.

This paper shows that although some of the concerns expressed by anti-legalization campaigns stem from the scientific literature, most reflect an incomplete picture and may be largely inaccurate. Cannabis’ risks to public health and safety are manageable, and targeted and evidence-based policy can ensure safe, legal markets for medical and recreational use.

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