How Has Legal Recreational Cannabis Affected Adolescents in Your State? A Window of Opportunity

As of postelection November 2016, seven states and one federal district in the United States have legalized recreational cannabis use for individuals aged 21 years and older—Alaska, California, Colorado, Massachusetts, Nevada, Oregon, Washington, and the District of Columbia—with more states likely to follow. Importantly, the states with the earliest recreational cannabis laws have had them for fewer than four years. This nascent period provides a tremendous opportunity for these states to inform health policy by examining data on cannabis use, particularly in the subset of the population most susceptible to the potential harms of drugs: our adolescents.

Adolescence marks one of the most impressive stretches of neural and behavioral change.¹ In line with the developmental process of addiction framework,² the use of cannabis and other substances is likely to incur relatively greater interference in neural, social, and academic functioning during adolescence than during later developmental periods.³ How recreational cannabis laws can or will affect adolescent health at the population level is, thus, a question of national concern.

Although no study has yet detected a significant change in cannabis use related to legalization,⁴ observing change (or the lack thereof) will take time because policy implementation and the shifting of substance use norms occur gradually. Further, investigations of potential cannabis use change are severely restricted because of the surprisingly limited amount and depth of current metrics. For example, national surveys (e.g., Monitoring the Future⁵; the Youth Risk Behavior Surveillance Survey⁶) capture broad patterns of behavior in this age group but not the fine-grained data needed to unravel the complicated picture of immediate and long-term cannabis sequelae. Data are needed on frequency of use (e.g., number of days per month; number of days per week; number of times per day), types of cannabis products used and mode of delivery (e.g., vaping vs edibles), means of obtaining cannabis (e.g., through friends, siblings, cannabis dispensaries), cannabis use before or after other risk behaviors (e.g., unprotected sex; alcohol, tobacco, opiate, or e-cigarette use), and potential social and health outcomes related to use (e.g., school disruption, changes in employment patterns, pregnancy, motor vehicle accidents).

Meticulous, focused assessments will critically disentangle the complex interplay of the social forces affecting drug use to help detect changes in adolescents’ cannabis use that can be causally attributed to new recreational legislation. Because such measures are still lacking, we do not know the answers to frequently asked questions addressing the relationship between state policy and adolescent health, such as the following:

• Does having cannabis dispensaries in neighboring areas increase youths’ cannabis use?

• Are cannabis dispensaries disproportionately located in neighborhoods with other health risk factors for children and adolescents?

• How do changes in cannabis advertising affect adolescents’ postlegalization cannabis use?

• Is there any change in the patterns of use of youths whose social networks include persons who are older than the legal cannabis use age?

• How has the change in cannabis policy affected the number and severity of accidents among youths who have consumed cannabis or ridden with a driver who is under the influence of cannabis?

• Does the form of cannabis packaging (e.g., candy and other edible forms) contribute to the risk of accidental consumption by underage persons?

• How will increased cannabis availability change the occurrence and need for identification and treatment of substance use disorder among adolescents?

Additionally, cannabis research with adolescents has specific challenges that hamper the scientific process. First, the heterogeneity of cannabis is without precedent among drug classes. Common clinical screening questions and survey instruments do not yet capture types, patterns, and severity of use. Consequently, establishing valid data collection instruments that reflect cannabis use patterns and routes of administration are needed to specifically, sustainably, and longitudinally track adolescent cannabis use with any replicable level of detail.

Second, the short timeline needed to answer key research questions does not map onto the protracted window that characterizes traditional scientific research funding sources. It often takes more than two years to go from scientific idea to federal funding. Without rapid routes for funding adolescent cannabis use research, we will miss the window to examine how adolescent cannabis use is changing in early adopting jurisdictions. More pragmatic and timely sources of research support may be local or national foundation awards and state public health agencies.

Third, the examination of the nature of cannabis use in a sample that is not using it legally adds an additional layer of practical complexity. Among adults, it is both legal and ethical to, for example, compare the effects of a substance such as alcohol on the brain and on behavior, before and after exposure. This allows us to examine how individuals respond after using a substance, thus generating concrete empirical data on the immediate impact of the substance on judgment, decision-making, and physical capacity. Although we are not advocating this approach, our inability to do this type of research with adolescents generates an obvious challenge to unraveling the acute effects of cannabis on the developing brain.

As other states consider initiatives to legalize cannabis for recreational use, timely evaluation to inform future legislation and patient care has become urgent. Lawmakers and the public need evidence to guide them in assessing the merits of any proposed legislation and to reduce the likelihood that adolescents will experience deleterious outcomes as a result of recreational cannabis legalization. All early adopting states included provisions for cannabis revenues to be used for public education and substance use treatment in their ballot measures; however, to our knowledge, these funds have not yet been directed to evaluation.

These “set-asides” are critically important. This type of funding would allow us to rapidly develop a foundation for large-scale evaluation of the effect of increased cannabis access on adolescents’ health.

The absence of data on the impact of cannabis use limits not only the scientific community and policymakers; in their day-to-day practice, pediatricians, who are in the role of counseling both parents and adolescent patients, remain woefully underprepared for conversations with patients about the potential risks of cannabis use. Until empirical data are available to guide clinical decision making, individual pediatricians and mental health practitioners, along with health systems and schools, must be prepared to recognize the limits of the knowledge base and counsel adolescents within these constraints.

The potential public health consequences of failing to allocate resources to timely evaluation may be similar to what we are facing in the opioid epidemic: virtually unchecked prescribing and use that proved extremely difficult to curb once the profound population-level harms became apparent. Timely, robust evaluation is requisite to ensure that we do not underestimate the impact of recreational cannabis legislation on adolescent use and development. Further, this will help ensure that policy reform recommendations are firmly and carefully grounded on empirical data rather than popular belief and speculation. Allowing science to move forward rapidly is imperative and would finally allow us to answer the question: “How has legalization of recreational cannabis affected adolescents in your state?”