People Who Use Marijuana May Be More Likely to Develop Other Substance Use Disorders

A prospective analysis of the results of a survey of U.S. adults suggests marijuana use may be associated with an increased risk for developing alcohol and drug disorders, but not mood or anxiety disorders, according to a study published today in JAMA Psychiatry.

“Our findings suggest caution in the implementation of policies related to legalization of cannabis for recreational use, as it may lead to greater availability and acceptance of cannabis, reduced perception of risk of use, and increased risk of adverse mental health outcomes, such as substance abuse disorders,” Mark Olfson, M.D., M.P.H., of Columbia University Medical Center and colleagues wrote.

Olfson and colleagues prospectively examined the associations of cannabis use with the prevalence and incidence of mood, anxiety, and substance abuse disorders in a nationally representative sample of 34,653 U.S. adults interviewed three years apart (wave 1: 2001 to 2002; wave 2: 2004 to 2005) as part of the National Epidemiologic Survey on Alcohol and Related Conditions.

Cannabis use was assessed by asking respondents whether they had used cannabis in the 12 months preceding the interview, and psychiatric disorders were measured according to DSM-IV using the Alcohol Use Disorder and Associated Disabilities Interview Schedule. Incidence refers to disorders that were reported at wave 2 among respondents without a lifetime history of the disorder at wave 1.

Analysis of the data revealed that cannabis use in wave 1, which was reported by 1,279 respondents, was significantly associated with substance use disorders in wave 2 (odds ratio of any alcohol use disorder, cannabis use disorder, and nicotine dependence were 2.7, 9.5, and 1.7, respectively), but not any mood disorder. However, the authors noted that the study was unable to determine a causal association between cannabis use and new onset of substance use disorders.

“While the health benefits of cannabis use require further testing among patients who are unresponsive to more traditional treatments, the association of cannabis use with negative mental health outcomes, such as substance use disorders, appears strong,“ the authors concluded.