The phenomenology of acute THC-psychosis
European Psychiatry January 1, 2009 P. Morrison, S. Kapur, R. Murray 1 citation
Intravenous delta-9-tetrahydrocannabinol (THC) can produce a temporary psychotic reaction in healthy people. In a double-blind, placebo-controlled experiment with 22 participants, a single 2.5 mg dose of THC significantly increased both self-reported and observer-rated positive psychotic symptoms, which were closely linked (correlation of 0.62). The symptoms involved a disrupted sense of self-agency and heightened paranoia. Participants also reported more negative symptoms, which were not due to sedation, and their working memory and executive function were consistently impaired. The findings suggest THC recreates symptoms across three major dimensions of schizophrenia without clouding consciousness. Preliminary evidence indicates that cannabidiol (CBD) may inhibit THC-induced positive symptoms.