No Causal Link Between Cannabis Use And Schizophrenia, Study Says

Honolulu, HI: Behavior suggestive of schizophrenia generally precedes the onset of cannabis use, according to survey data published in the current issue of the journal Psychiatry Research.

One-hundred and eighty-nine volunteers responded to an anonymous questionnaire inquiring about cannabis use and schizotypal traits (behavior suggestive of schizophrenia but not of sufficient severity to warrant a diagnosis of schizophrenia). Among recent cannabis users, average age of schizotypal symptoms significantly preceded age of first use of cannabis. When cases were analyzed individually, authors affirmed that the majority of respondents in the “Recently Used” group reported schizotypal personality disorder (SPD) symptoms prior to their initiation of cannabis use.

“Although researchers recognize an association between cannabis use and psychosis, whether or not cannabis contributes to the development of psychosis remains less clear,” authors wrote. “The current study … suggest[s] a temporal precedence of schizotypal traits before cannabis use in most cases. These findings do not support a causal link between cannabis use and schizotypal traits.”

For more information, please contact Paul Armentano or Allen St. Pierre of NORML at (202) 483-5500. Full text of the study, “Symptoms of schizotypy precede cannabis use,” appears in the March issue of Psychiatry Research.