Scientific consensus on the role of marijuana in psychological disorders is still lacking, after hundreds of years of speculation and study. Recent evidence of dysregulation of the body’s endocannabinoid system in schizophrenics is beginning to shed new light on some of these questions. This chapter, part of a clinical neurology book, discusses these issues. The authors find evidence that the vast majority of users are not adversely affected, and even may benefit from use in those with depression, bipolar and anxiety. The issue of marijuana and schizophrenia remains unsettled, but the authors argue, “A simple causative effect by which cannabis use may induce schizophrenia in otherwise normal individuals is hardly tenable.”

Ester Fride and Ethan Russo, “Neuropsychiatry: Schizophrenia, Depression and Anxiety,” in Endocannabinoids: The Brain and Body’s Marijuana and Beyond, Chapter 15, ed. Emmanuel S. Onaivi, Takayuki Sugiura and Vincent Di Marzo, (Boca Raton, FL: Taylor & Francis, 2006), 371-382.

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