According to a preliminary study, cannabis could bring on temporary paranoia and other psychotic like effects in people who have a high risk of developing a psychotic disorder.
The study was done by researchers at Columbia University Medical Center (CUMC) and was published last month in an online edition of Psychiatry Research.
Margaret Haney, PhD is a professor of neurobiology (in Psychiatry) at CUMC and was the senior author of the paper. She states, “Many adolescents and young adults who are at high risk for psychosis smoke marijuana regularly or have a cannabis use disorder. Yet researchers haven’t studied the effects of marijuana in this population in a rigorous, controlled manner.”
The study was a double-blinded, placebo-controlled laboratory study where researchers looked at the effects of marijuana in six high-risk young adults and six controls. The adults were all physically healthy.
As part of the study, participants smoked half of an active or placebo marijuana cigarette and had psychological and physiological assessments before and after smoking. The procedure was then repeated but with an active or placebo cigarette.
Researchers found that both groups had signs of intoxication and increases in heart rate and arousal relative to the placebo. They also found that the high-risk group experienced transient increases in paranoia and anxiety, as well as disrupted sensory perception and cognitive performance, after using active marijuana. Neither group had these effects after using the placebo.
First author on the paper, Nehal Vadhan PhD, who is a psychologist and associate professor in Psychiatry and Molecular Medicine at Hofstra Northwell School of Medicine, stated, “Although this was a small, preliminary study, it suggests that marijuana may affect individuals at high risk for psychosis differently than other marijuana users, by briefly inducing psychotic-like experiences and impairing their cognition. While larger studies are needed to confirm these findings, they may aid clinicians in their guidance to individuals at risk for psychosis about marijuana’s potential effects.”