Cannabis and psychopathology : update 2004.

The study of cannabis use and psychopathology remains an interesting area from both academic and pragmatic perspectives. This article provides an update on the progress made in this area over the past decade or so. Psychopathology and psychiatric syndromes associated with cannabis use that have received research attention in recent years include cannabis withdrawal, cannabis and psychotic disorders (especially schizophrenia), depression, anxiety, and cognitive impairment. Status of a specific cannabis withdrawal syndrome and a specific 'cannabis psychosis' remains controversial. Current evidence indicates that there is a clinically significant association between cannabis use disorders and psychotic syndromes, depression, anxiety and possibly mild cognitive impairment. However, the nature of this association is often not clear. Several hypothesis related to the cannabis-schizophrenia association are examined. Cannabis use might be casually related to the later development of schizophrenia in an indirect way in a few heavy users, but more commonly, its use may precipitate disorders in persons who are vulnerable to developing psychosis and worsen the course of the disorder.