Cannabis use may increase risk for self-reported psychotic disorders

Frequent nonmedical cannabis use and cannabis use disorder appeared linked to self-reported psychotic disorders, according to study results published in American Journal of Psychiatry.

The study included data from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC).

“One study of NESARC data (30) showed associations between lifetime self-reported psychosis and a combined substance use disorder category, but provided little information specific to cannabis,” Ofir Livne, MD, of the department of epidemiology at Columbia University Mailman School of Public Health in New York, and colleagues wrote. “Other NESARC studies showed associations of lifetime self-reported psychosis with cannabis use and cannabis use disorder, but these studies did not address current (past-year) disorders, and also reported on data collected before the substantial increases in adult cannabis use, cannabis potency and cannabis use disorder since the mid-2000s.”

Because of widespread changes related to cannabis in the U.S. in recent years, the researchers noted the importance of investigating whether the prevalence of self-reported psychosis and its link to cannabis use of cannabis use disorder have changed over time. In the current study, they analyzed data of 43,093 participants of NESARC between 2001 and 2002 and 36,309 participants of NESARC-III between 2012 and 2013.

Via logistic regression, they estimated standardized prevalence of past-year self-reported psychotic disorders for each survey and assessed the link between past-year self-reported psychotic disorders with nonmedical cannabis use indicators compared with participants with no past-year nonmedical cannabis use. Further, the researchers used difference-in-difference tests and ratios of ORs between surveys to determine whether the strength of associations differed between surveys.

Participants with any nonmedical cannabis use had significantly higher rates of self-reported psychotic disorders compared with those without use, with 1.65% vs. 0.27% between 2001 and 2002 and 1.89% vs. 0.68% between 2012 and 2013, respectively. Self-reported psychotic disorders did not appear associated with either frequent use or daily/near-daily use between 2001 and 2002; however, between 2012 and 2013, participants with frequent use (2.79%) and daily-near-daily nonmedical cannabis use (2.52%) had higher rates of self-reported psychotic disorders than nonusers (0.68%). In both surveys, participants with cannabis use disorder had significantly higher prevalence of self-reported psychotic disorders compared with nonusers, for 2.55% vs. 0.27% between 2001 and 2002 and 3.38% vs. 0.68% between 2012 and 2013. These associations retained their strength over time.

“This information can inform addiction specialists and other clinicians about the need for evaluation and appropriate interventions and therapeutic modalities for individuals at risk,” Livne and colleagues wrote. “Further, although not directly examined in this study, policy makers should be aware of the increase in cannabis use and cannabis use disorder among U.S. adults, and any possible subsequent increase in cannabis-related outcomes, including psychotic disorders.”