Cannabis Use Increases the Risk of Substance Use Disorder
In the context of the legalization of marijuana use in some US states (both for recreational and medical use) and of rising rates of use in the general population, it is important to assess the effect of cannabis use on mental health problems. Using data from the National Epidemiologic Survey on Alcohol and Related Conditions waves 1 and 2, researchers examined the prospective associations between cannabis use and substance use disorder (SUD) and mood and anxiety disorders 3 years later.
- In unadjusted analyses, cannabis use was associated with an increased prevalence and incidence of SUD and mood and anxiety disorders.
- In adjusted analyses,* cannabis use was associated with an increased prevalence and incidence of SUD, but not mood and anxiety disorders.
- Cannabis use was associated with alcohol use disorder (prevalence: odds ratio [OR], 2.5; incidence: OR, 2.7), cannabis use disorder (prevalence: OR, 12.4; incidence: OR, 9.5), other drug use disorder (prevalence: OR, 3.1; incidence: OR, 2.6), and nicotine dependence (prevalence: OR, 1.5; incidence: OR, 1.7).
* Adjusted for potential confounders from childhood (family history of SUD, parental loss, vulnerable family environment); early adolescence (low self-esteem, age of onset of anxiety disorders, social deviance); late adolescence (educational level, personality disorders, number of psychiatric disorders on axis I before age 18); adulthood (divorce, history of SUD, social deviance), in addition to age, sex, race/ethnicity.
Comments:
The adjusted analyses indicate that associations between mood and anxiety disorders and cannabis use can be explained by differences in the distribution of confounders between people with cannabis use and those without. Even though the present study does not prove causation, the strong associations between cannabis use and SUD are biologically plausible and are of importance given the morbidity and mortality associated with SUD. Caution is needed when implementing policies legalizing recreational cannabis use.
Nicolas Bertholet, MD, MSc
Reference:
Blanco C, Hasin DS, Wall MM, et al. Cannabis use and risk of psychiatric disorders: prospective evidence from a US national longitudinal study. JAMA Psychiatry. 2016;73(4):388–395.