People who frequently use cannabis and/or those with cannabis use disorder are more likely to report having been diagnosed with a psychotic disorder than those with no past-year cannabis use, according to a report in AJP in Advance. The study also found evidence to suggest psychotic disorders in the adult U.S. population rose from 2001-2002 to 2012-2013.
“Our finding that the prevalence of past-year self-reported psychosis increased significantly between 2001-2002 and 2012-2013 is the first reported change in prevalence of self-reported psychotic disorders based on large-scale, nationally representative samples of U.S. adults,” wrote Ofir Livne, M.D., of the Columbia University Mailman School of Public Health and colleagues.
The findings were based on data collected from more than 79,000 people during two waves of NIAAA’s National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), conducted 10 years apart. Livne and colleagues specifically focused on self-reports of psychotic disorders by survey respondents with varying levels of cannabis use: any nonmedical use, frequent nonmedical use, daily/near-daily nonmedical use, or a diagnosis of DSM-IV cannabis use disorder. Nonmedical use was defined as use without a prescription or other than prescribed. (The NESARC did not include a question about medical use of cannabis, precluding examination of this question in NESARC data.) Respondents were classified as having a self-reported psychotic disorder if they had been told by a medical professional that they had schizophrenia or psychotic illness or episode.
In the 2001-2002 survey, 178 of 43,093 respondents had a self-reported psychotic disorder. In the 2012-2013 survey, 337 of 36,309 respondents had a psychotic disorder.
Participants with cannabis use disorder reported in the 2001-2002 survey had a higher rate of self-reported psychotic disorders than nonusers (2.55% compared with 0.27%); in the 2012-2013 survey the difference was even greater (3.38% compared with 0.68%).
In the 2012-2013 survey (but not in the 2001-2002 survey) people who frequently used nonmedical cannabis were more likely to have a psychotic disorder than nonusers (2.79% compared with 0.68%).
“The increasing perception of cannabis as a harmless substance may deter the general public as well as health care providers from recognizing that nonmedical cannabis use may play a role in exacerbating the risk for psychotic disorders,” the researchers wrote. “[I]mproving public knowledge and educating providers about this risk may serve a useful function.”
For related information, see the Psychiatric News article “Daily and High-Potency Use of Cannabis Linked to Psychosis.”
(Image: iStock/Yarygin)
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