In humans, however, the role of cannabinoids on fear extinction learning remains unknown. The primary goal of this study was to test the hypotheses that administration of an exogenous CB1 agonist would enhance the memory and maintenance of fear extinction. In a randomized, double-blind, placebo-controlled, between-subjects design, we coupled a standard Pavlovian fear conditioning and extinction paradigm with an acute pharmacological challenge with oral dronabinol (synthetic THC) or placebo 2 hours prior to extinction learning in healthy adult volunteers and tested extinction retention 24 hours after extinction learning.
