By Charles Bankhead, Staff Writer, MedPage Today Published: February 27, 2010 Reviewed by Dori F. Zaleznik, MD; Associate Clinical Professor of Medicine, Harvard Medical School, Boston.

Marijuana use at a young age significantly increased the risk of psychosis in young adulthood, Australian investigators reported.

Young adults who reported a longer duration since first exposure to marijuana had a two- to fourfold greater prevalence of three different psychosis-related outcomes, John McGrath, MD, PhD, of the Queensland Center for Mental Health Research in Wacol, and colleagues concluded in an article published online in Archives of General Psychiatry.

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