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3 Essential Questions: Drug Policy and its Consequences

November 03, 2021
by Michael Greenwood

Jason Hockenberry, Ph.D., professor and chair of the Department of Health Policy and Management at the Yale School of Public Health, is a health economist who studies the effects of public health policies to assess factors affecting the quality, efficiency and cost of health care. This includes examining the consequences of public policies that restrict or liberalize access to particular substances (e.g. opioids and cannabis) or treatments (e.g. buprenorphine), and the effects of these and other substance use policies on health, functioning, and social outcomes, such as crime and employment.

Connecticut and a host of other states have legalized the use of recreational marijuana. Is this good policy in terms of public health?

JH: When we are helping Yale students develop their understanding of and ability to evaluate policy one of the first things we discuss is the importance of defining what ‘good’ policy is. In the case of the liberalization of cannabis, as with other substances of potential misuse or abuse that also involve criminal justice considerations, evaluating the effects of a policy change are complex.

In terms of health outcomes, whenever the legal status of a substance changes patterns of use and views of the risk of use change. The question for the policy and research community is whether in totality these changes to cannabis policy make us better or worse off at a population level. Historically the concern among public health experts regarding liberalization has been for two reasons. First, there are concerns of negative long-term consequences for mental health and outcomes if cannabis consumption begins in adolescence or early adulthood, or consumed at persistently high rates. Second, the liberalization of cannabis would lead to a gateway phenomenon whereby some parts of the population, particularly young people, would transition to more dangerous drugs. At the same time others have argued that cannabis is less dangerous than other legal substances like alcohol and has the potential to substitute for some of these more dangerous substances and reduce outcomes like opioid misuse and overdose, a phenomenon that those in public health refer to as harm reduction.

So, what’s the evidence say?

To date, research indicates that liberalization of cannabis under medical use laws had at most modest effects on use and misuse in young adults, with scant early evidence of a gateway effect or changes in patterns of use among adolescents. Research on attitudes indicates that the perception of health risks of cannabis use is shifting toward a perception of less risk, including among younger people, which could influence future patterns of use.

Liberalization to the level of recreational use is relatively recent, and the evidence on the effects of these laws is still emerging and their effects will take some time to fully manifest. In general, with less restrictive access we would anticipate an increase in use. As with medical liberalization laws, we anticipate a shift in perceptions of risk as well. As that unfolds, research will need to be done to update the understanding of the effects of policy on initiation, long term use, and associated health and social outcomes.

Our current national conversation about social equity and justice provides another lens through which we should view these changes in the law. Arguably, in the case of cannabis, a large portion of the potential harm to society from restrictive policy is tied to the connection between cannabis and criminal justice outcomes. Cannabis arrests, many of which are for low level possession offenses, accounted for more than half of substance related arrests a decade ago. That proportion had dropped to about 40% just prior to the pandemic. So that is an encouraging sign. However, there is a historical disparity in cannabis related arrest rates between Blacks and whites, with Blacks subject to an arrest rate for cannabis that was nearly 4 times greater than whites despite self-reported use of cannabis being similar in the two populations. There were some encouraging trends in the mid-2010’s that this gap was narrowing, but then it started to widen again. Many advocates and researchers in criminal justice, public policy, and public health are working to understand the mechanisms behind this disparity so that this structural inequity can be addressed, and to understand whether liberalization is an essential element to doing so.

Will legalized marijuana result in increased use? Over time, will legalization affect how much people use other drugs?

JH: There is evidence that liberalization of cannabis has increased cannabis consumption with increasing rates of misuse in some segments of the population, particularly young adults who are 21 or older. The relationship with patterns of use of other substances is mixed. There is some evidence that liberalization has reduced opioid use, as cannabis can serve either as a complete substitute for opioids for use in pain control or cannabis can be coupled with opioids to reduce the need for increasing doses of the latter to achieve the same level of pain control. There are two important caveats to this research. First is that the evidence to date is largely at the population level, and some subgroups may have different patterns of use and outcomes. Second is that these law changes allowing recreational use are relatively new, so the observed effects are by definition the short-term effects of these laws. Continued monitoring is needed to understand how some of the more complex interactions of health and social outcomes unfolds, and as a society we need to be ready to adjust policy accordingly.

You’ve said that opioid use is a defining health challenge of the past decade. What do you see in the decade ahead in terms of its use, overdoses and deaths?

JH: Yes, at some point the COVID-19 pandemic will hopefully be under control. And at that point substance misuse and abuse, particularly of opioids and in combination with other substances, will remain as a major contributor to early mortality and increased morbidity. The trends in opioid related policy development is to try to restrict the supply of prescribed opioids to cases where necessary and to limit duration, which should reduce the size of the population transitioning to misuse or abuse. However, a sizable population has already been exposed and are at increased risk for long term health threats from opioid use. In addition, we are facing a vastly different context in terms of the illicit supply of opioids available in the United States. Taken together this means we still need substantial investments to abate this serious threat to the health of our population. This means increased treatment referral and working to reduce barriers to access.

3 Essential Questions is a recurring feature that explores vital topics in public health. Read earlier versions of 3 Essential Questions on cancer and antibiotic resistance and climate change.

MEDIA CONTACT: Michael Greenwood at

Submitted by Ivette Aquilino on November 03, 2021