Link between Adolescent Pot Smoking and Psychosis Strengthens - Scientific American Research presented at a Berlin psychiatric conference shows teenage cannabis use hastens onset of schizophrenia in vulnerable individuals Society’s embrace of cannabis to treat nausea, pain and other conditions proceeds apace with the drive to legalize the plant for recreational use. Pot’s seemingly innocuous side effects have helped clear a path toward making it a legal cash crop, with all of the marketing glitz brought to other consumer products. But that clean bill of health only goes so far. Marijuana’s potentially detrimental impact on the developing brains of adolescents remains a key focus of research—particularly because of the possibility teenage users could go on to face a higher risk of psychosis. New findings may fuel those worries. At the World Psychiatric Association’s World Congress in Berlin on October 9, Hannelore Ehrenreich of the Max Planck Institute of Experimental Medicine presented results of a study of 1,200 people with schizophrenia. The investigation analyzed a wide range of genetic and environmental risk factors for developing the debilitating mental illness. The results—being submitted for publication—show people who had consumed cannabis before age 18 developed schizophrenia approximately 10 years earlier than others. The higher the frequency of use, the data indicated, the earlier the age of schizophrenia onset. In her study neither alcohol use nor genetics predicted an earlier time of inception, but pot did. “Cannabis use during puberty is a major risk factor for schizophrenia,” Ehrenreich says.