Cannabis and schizophrenia spectrum disorders: a review of clinical studies.
Indian journal of psychological medicine July 1, 2009 Chaturaka Rodrigo, Senaka Rajapakse
Cannabis use has increased by 10% worldwide over the last decade, prompting a review of its possible link to schizophrenia spectrum disorders (SSD). The authors searched MEDLINE and other sources for English-language articles from 1999-2009. They discuss biochemical evidence on cannabinoids and the endocannabinoid system, and clinical studies on cannabis, psychosis proneness, and SSD. Three hypotheses are examined: that cannabis causes SSD, that schizophrenic patients are attracted to cannabis, and that cannabis and psychosis proneness have synergistic effects in a vulnerable minority. The evidence does not firmly support causation or self-medication; the most plausible explanation is a synergistic effect in some individuals.