Medical Cannabis Legalization: No Contribution to Rising Stimulant Rates in the USA

There has been a pronounced increase in the use of Schedule II stimulants to treat attention-deficit hyperactivity disorder (ADHD) in the United States over the last two decades. Interestingly, chronic medical cannabis (MC) use can present with cognitive impairments that resemble ADHD symptoms. This study aimed to determine if MC legalization increased prescription stimulant distribution.

Information on the distribution of methylphenidate, amphetamine, and lisdexamfetamine for 2006 to 2021 was extracted from the Drug Enforcement Administration's comprehensive database and the three-year population-corrected slopes of stimulant distribution before and after MC program implementation were compared.

We found a significant main effect of time (p<0.001); however, contrary to the hypothesis, the sales status of states' MC, did not influence slopes of distribution (p=0.391). There was a significantly large interaction effect of time and MC sales status on slopes of distribution (p<0.001). Slopes of distribution rates of stimulants were significantly lower in states that proceeded to legalize MC prior to MC program implementation than those states that did not (p=0.022). After MC program implementation, however, the distribution rates of the Schedule II stimulants were not significantly different when comparing states with MC sales to those without (p=0.355).

These findings suggest that MC program legalization did not contribute to certain states having rapid increases in Schedule II stimulant distribution rates over time. Other factors, including the liberalization of the adult ADHD diagnostic criteria in the DSM-5 and the introduction of Binge Eating Disorder, also likely contributed to elevations in stimulant distribution.