Marijuana is commonly smoked to reduce feelings of stress and anxiety (Kogan and Mechoulam, 2007), though paradoxically its primary psychoactive constituent, Δ9-tetrahydrocannabinol (THC), can also increase anxiogenic-like behaviors (Onaivi et al., 1990). Other adverse side effects of cannabis use, including cognitive deficits, abuse potential, and dependence liability, have dampened enthusiasm for the therapeutic development of THC and other cannabinoid receptor agonists. Instead, much interest has been generated by the discovery of the endogenous cannabinoid (i.e. endocannabinoid; eCB) system as a source of targets for the development of new therapeutic treatments of a range of ailments including anxiety and depression (Pacher et al., 2006).
