Substance Abuse & Schizophrenia

Heavy methamphetamine use may increase the risk of developing schizophrenia, according to a new study published online November 8th in the American Journal of Psychiatry. The study confirmed previous research showing a possible link between marijuana dependence and schizophrenia. Researchers at the Centre for Addiction and Mental Health (CAMH) in Toronto analyzed the records of patients who were admitted to California hospitals between 1990 and 2000 with a diagnosis of dependence or abuse for methamphetamine, marijuana, alcohol, cocaine or opioids. People who were hospitalized for meth dependence and who had never been diagnosed with schizophrenia or psychotic symptoms at the start of the study had a roughly 1.5- to three-fold higher risk of later being diagnosed with schizophrenia than patients who used cocaine, alcohol or opioid drugs. Researchers also found that the increased risk of schizophrenia in methamphetamine users was similar to that of heavy users of marijuana.