Study Questions Validity Of So-Called “Cannabis-Induced Psychosis”
Aarhus, Denmark: People who experience long-lasting psychotic episodes after consuming cannabis may be exhibiting early signs of schizophrenia, according to clinical trial data published in the journal Archives of General Psychiatry.
Investigators at a pair of Denmark universities compared the family histories of 609 people treated for so-called “cannabis-induced psychosis” and 6,476 individuals who had been treated for schizophrenia or a related psychiatric condition. Researchers found that people treated for post-pot “psychosis” were just as likely to have a family history of schizophrenia as were those diagnosed with the mental illness. “Cannabis-induced psychosis could be an early sign of schizophrenia rather than a distinct clinical entity,” researchers concluded.
Researchers said that their finding challenge the hypothesis that heavy marijuana use may cause schizophrenia in a minority of users, noting, “These people would have developed schizophrenia whether or not they used cannabis.”
Despite recent claims purporting a potential link between cannabis use and mental illness, there is no empirical data indicating a rise in incidences of schizophrenia in populations with statistically higher rates of marijuana use.
For more information, please contact Paul Armentano, NORML Deputy Director. Full text of the study, “Comparison of subjects treated for cannabis-induced psychosis and schizophrenia,” appears in the Archives of General Psychiatry.
People who have long-lasting psychotic episodes after cannabis use may be exhibiting early signs of schizophrenia, researchers of Aarhus University, Denmark, reported. Between 1994 and 2005, 609 individuals received treatment of a cannabis-induced psychosis and 6476 received treatment of a schizophrenia spectrum disorder. Predisposition to both psychiatric disorders contributed equally to the risk of later treatment because of schizophrenia and cannabis-induced psychoses. Researchers concluded from the results of their study that “cannabis-induced psychosis could be an early sign of schizophrenia rather than a distinct clinical entity.” (Source: Arendt M, et al. Arch Gen Psychiatry 2008;65(11):1269-74.)