Context Cannabis use can both increase and reduce anxiety in humans. The
neurophysiological substrates of these effects are unknown. Objective To investigate the
effects of 2 main psychoactive constituents ofCannabis sativa (Δ9-tetrahydrocannabinol [Δ9-
THC] and cannabidiol [CBD]) on regional brain function during emotional processing.
Design Subjects were studied on 3 separate occasions using an event-related functional
magnetic resonance imaging paradigm while viewing faces that implicitly elicited different …