Study Linkspot Use,psychosis

February 28, 2018 GMT

Q: Could you comment on the marijuana study done in early 2016 at the University of Exeter and University College London? I’m worried about the 14-year-olds with whom I work and their dangers of psychosis. I was hoping we might start a dialogue about the risky business of marijuana. A: One of the big concerns about marijuana use, especially among adolescents and young adults, is the connection to psychotic episodes and lifelong schizophrenia. In people with a family history of schizophrenia, marijuana can increase the risk of such episodes and decrease the age of schizophrenia onset. The study to which you refer sheds some light on that risk. That study focused on the AKT1 gene, which has been proposed as a possible genetic connection to this response to marijuana. The gene produces the enzyme serine-threonine protein kinase, necessary for many cellular processes throughout the body — including the transmission of dopamine, which carries signals between brain cells. This function is known as dopamine signaling, and proper signaling is necessary for the brain responses controlling behavior and emotion. As background, studies in mice have shown that marijuana activates the AKT1 gene in the brain’s cerebellum, hippocampus and striatum. Second, schizophrenia has been linked to disturbed and hyperactive dopamine signaling. The concern is that, if AKT1 is stimulated by marijuana — increasing dopamine transmission in the brain — then psychosis may occur. The study you mention looked at 422 people, ages 16 to 23, who used marijuana at least once a month. Participants were given a pair of psychological tests at two different times: once without the use of marijuana and once with use. One psychological test was designed to detect psychotic symptoms; the other test was designed to detect dissociative and imaginative states, also called schizotypal symptoms, similar to those seen in schizophrenia. The researchers also did genotype testing to identify people with the AKT1 2494732 type. Of the 422 participants, 197 had one copy of the gene and 91 had two copies. When intoxicated with marijuana, people with one or two copies of the AKT1 2494732 type had moderately greater psychotic symptoms, but other participants were not free of symptoms. Also, interestingly enough, schizotypal symptoms were not associated with this gene type, but were associated with a dependency to marijuana. People who were both dependent on marijuana and who had the AKT1 genotype were more likely to have psychotic symptoms. ASK THE DOCTORS is written by Robert Ashley, M.D., Eve Glazier, M.D., and Elizabeth Ko, M.D. Send questions to askthedoctors@ mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095.