Distinct Effects of Δ9-Tetrahydrocannabinol and Cannabidiol on Neural Activation During Emotional Processing
Archives of General Psychiatry January 1, 2009 Paolo Fusar‐poli, José A. Crippa, Sagnik Bhattacharyya et al. 461 citations
In healthy men with minimal prior cannabis use, the two main psychoactive compounds in cannabis had opposite effects on anxiety and brain activity. Delta9-tetrahydrocannabinol (THC) increased anxiety, intoxication, sedation, and psychotic symptoms, while cannabidiol (CBD) showed a trend toward reducing anxiety. When participants viewed intensely fearful faces, THC increased skin conductance fluctuations (a measure of autonomic arousal), whereas CBD decreased them. CBD also dampened brain activation in the amygdala and anterior and posterior cingulate cortex, and this suppression correlated with reduced arousal. THC mainly altered activation in frontal and parietal areas. These distinct neural effects may explain why cannabis can both relieve and provoke anxiety.