Studies are showing that if an individual has a tendency towards, or are diagnosed with a psychological disorder, they may want to be careful with consuming too much THC. The body naturally produces a neurotransmitter inhibitor called GABA which slows excitement in the brain, and THC is capable of blocking it. Some individuals overproduce dopamine which creates excitement in the brain and if it is left unchecked it can trigger psychotic episodes. THC is not found in all medical marijuana products though. Cannabidiol (CBD) is found in marijuana and has a number of medicinal benefits, including pain and inflammation reduction, but with no psychoactive effects. You should consult with your doctor before ingesting a marijuana product.
Exposure to THC, the active cannabinoid found in marijuana that has a psychoactive effect, can trigger psychotic episodes especially in people that already have a psychotic disorder or tendencies towards them. THC can make the brain hyperactive and allow dopamine to run unregulated in the brain.
Unchecked dopamine is a signature of schizophrenia and Parkinson’s disease, which would typically be put in check by the production of an acid called GABA. GABA production can be stifled by exposure to THC which is the direct problem for someone that has a psychotic disorder or a tendency towards psychotic episodes in the first place.
Individuals who have had mild or transient psychotic symptoms (such as unusual thoughts, suspiciousness, perceptual disturbances) without using substances such as marijuana or alcohol and have a family history of psychosis or other risk factors are considered at clinical high risk for psychotic disorder. Previous studies have found an association between marijuana use and psychosis in the general population, but none have rigorously examined marijuana’s effects in those at greatest risk for psychosis.
“Many adolescents and young adults who are at high risk for psychosis smoke marijuana regularly or have a cannabis use disorder,” said Margaret Haney, PhD, professor of neurobiology (in Psychiatry) at CUMC and senior author of the paper. “Yet researchers haven’t studied the effects of marijuana in this population in a rigorous, controlled manner.”
In this double-blinded, placebo-controlled laboratory study, the researchers looked at the effects of marijuana in six high-risk young adults and six controls, all experienced and current marijuana smokers who were physically healthy. Participants smoked half of an active or placebo marijuana cigarette, had psychological and physiological assessments before and after smoking, and then repeated this procedure with the opposite (active or placebo) cigarette.
After smoking active marijuana, both groups had signs of intoxication and increases in heart rate and arousal relative to the placebo. However, only 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 experienced these effects after using the placebo.
“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,” said Nehal Vadhan, PhD, a psychologist and associate professor in Psychiatry and Molecular Medicine at Hofstra Northwell School of Medicine and first author of the paper. “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.”