Medical marijuana: Stepping stone or protective effect?

Abstract

Aims: Following implementation of medical marijuana laws around the U.S., concerns have been raised that greater availability and acceptance of marijuana could be associated with increased use of illicit drugs among young adults, which follows the logic of the stepping stone theory. However, other research suggests that regular access to marijuana through medical marijuana programs may offer a protective effect against initiating other drugs. Methods: A total of 301 young adults (18-25 years old) were recruited in Los Angeles between 2009 and 2011 as part of a study focusing on prescription drug misuse. Among the sample, 56 (18.6%) reported being a current medical marijuana patient (MMP) compared to 245 (81.4%)who were non-patient users (NPU) of marijuana. Participants were administered a cross-sectional survey and answered a range of questions pertaining to history of marijuana use, illicit drug use, and prescription drug misuse. Results: First, a “maturing out” process occurred among NPU: fewer members of the oldest cohort used marijuana in the past 90 days compared to the youngest cohorts (48.7% vs. 67.8%). In contrast, no maturing out process occurred among MMP: each age cohort reported nearly identical marijuana use (approximately 80% reported use of marijuana in the past 90 days). Overall, a greater proportion of MMP reported 90 day use of marijuana compared to NPU (80.2% vs. 64%). Second, a significantly smaller proportion of MMP reported lifetime use of three key illicit drugs compared to NPU: ecstasy (75% vs. 87.3%); cocaine (67.9% vs. 83.7%); and methamphetamine (48.2 vs. 64.5%). Also, a lower proportion of MMP reported lifetime misuse of OxyContin and Xanax compared to NPU (but not statistically significant). Conclusions: Among MMP in this study, a greater proportion were recent marijuana users and a lower proportion were lifetime users of illicit and prescription drugs. Among NPU, the reverse was true. Overall, these findings provide preliminary evidence to suggest that among young MMP, marijuana could provide a protective effect against initiating illicit and prescription drugs.