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, the authors suggest that activation patterns detected by fMRI may be a more relevant indicator of the centralized effects of THC on conscious threat perception than behavioral measures, or that the self-report scales used, which were visual analog scales, may not be sensitive to the emotion or fear specific changes elicited by THC for the stimuli used. In either case, administration of THC altered amygdalar reactivity in response to overt social signals of threat in casual marijuana users, raising the likelihood that similar alterations in neural networks associated with affective processing would be detected using non-overt or masked stimuli in chronic, heavy marijuana smokers.
