Results from this study are consistent with those of Phan and colleagues who utilized fMRI and a variation of the Emotional Face Processing Task in occasional marijuana smokers after the acute administration of oral THC or placebo (Phan et al., 2008). Briefly, this task requires subjects to match a target, consisting of either an emotional face (angry, fearful or happy) or a shape, with one of two choices, and has been shown to produce robust amygdalar activity during pharmacologic challenges (Hariri et al., 2002; Paulus et al., 2005). During the placebo condition, amygdalar activity was greater for threatening (angry, fearful) faces than non-threatening (happy) faces. In contrast, administration of THC significantly attenuated amygdalar activity in response to both types of threatening faces (angry or fearful). Interestingly, the extent of amygdalar attenuation was positively related to extent of increase of “feeling drug” reported by subjects on the Drug Effects Questionnaire. Given that subjects did not report any change in their reported levels of anxiety (neither an increase nor a decrease) following the THC administration, yet the drug attenuated threat-related amygdalar activity,
