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Cannabis use may increase risk for substance use disorders, not mood disorders

Cannabis use was associated with increased risk for substance use disorders but not mood or anxiety disorders, according to recent findings.

“Rising rates of recreational marijuana use and the changing legal status of cannabis across the United States have intensified debate regarding the mental health consequences of cannabis use. Although medical use of cannabis may benefit a selected group of patients, systematic scientific evidence supporting these claims remains limited, while the adverse consequences of cannabis use have been extensively documented,” Carlos Blanco, MD, PhD, of the National Institute on Drug Abuse, Bethesda, Maryland, and colleagues wrote.

To investigate associations between cannabis use and risk for mental health and substance use disorders in the general population, researchers analyzed interviews from a nationally representative sample of adults aged 18 years and older in the National Epidemiologic Survey on Alcohol and Related Conditions. Primary analyses included 34,653 respondents who interviewed in both waves, 3 years apart. Psychiatric disorders were determined via the Alcohol Use Disorder and Associated Disabilities Interview Schedule-DSM-IV.

Cannabis use in wave one, which occurred from 2001 to 2002, was significantly associated with substance use disorders in wave two in 2004 to 2005. Odds ratios were 6.2 (95% CI, 4.1-9.4) for overall substance use disorder; 2.7 (95% CI, 1.9-3.8) for any alcohol use disorder; 9.5 (95% CI, 6.4-14.1) for any cannabis use disorder; 2.6 (95% CI, 1.6-4.4) for any other drug use disorder; and 1.7 (95% CI, 1.2-2.4) for nicotine dependence.

Conversely, cannabis use in wave one was not significantly associated with mood disorders (OR = 1.1; 95% CI, 0.8-1.4) or anxiety disorder (OR = 0.9; 95% CI, 0.7-1.1).

Researchers observed the same general pattern in multiple regression analyses of prevalent psychiatric disorders in wave two and propensity score-matched analysis of incident and prevalent psychiatric disorders.

“Our study indicates that cannabis use is associated with increased prevalence and incidence of substance use disorders. These adverse psychiatric outcomes should be taken under careful consideration in clinical care and policy planning,” the researchers concluded. – by Amanda Oldt

Disclosure: The researchers report no relevant financial disclosures.