Nonmedical versus medical marijuana use among three age groups of adults: Associations with mental and physical health status.

BACKGROUND AND OBJECTIVE: Given that 29 U.S. states now have laws allowing medical marijuana use, this study examined mental and physical health correlates of medical versus nonmedical marijuana use among three age groups of adults (18-29, 30-49, and 50+).

METHODS: Data came from the 2012-2013 National Epidemiologic Survey on Alcohol and Related Conditions (N = 36,309 respondents aged 18+). Logistic regression models were used to examine age group differences in associations of substance use and mental disorders and health conditions with medical versus nonmedical marijuana use.

RESULTS: Of all respondents, 9.74% (N = 3,784) reported past-year marijuana use. Of all past-year marijuana users, 11.03% (n = 445) reported medical use. Medical marijuana use rates were higher among the 50-64 age group (17.95%) than younger adults, and 32.88% of medical users, compared to 25.25% of nonmedical users, had past-year marijuana use disorder. The odds of medical marijuana use were higher among those with marijuana use disorder (OR = 1.87, 95% CI = 1.40-2.50) and personality disorder (OR = 1.42, 95% CI = 1.03-1.94), with no age group differences. However, older adults with alcohol use disorder and sleep problems and middle-age adults with arthritis had diminished odds of having used medical marijuana relative to young adults.

CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE: Given the high rates of marijuana use disorder among medical users, physicians should exercise caution in recommending marijuana for medical purposes, especially for younger adults. More research is needed on medical marijuana's safety and efficacy for patients at risk of marijuana use disorder. (Am J Addict 2017;26:697-706).