The effects of Δ9-tetrahydrocannabinol upon fear-motivated behavior in squirrel monkeys

Abstract

The present study investigated the effects of three doses (4.0, 8.0, 12.0 mg/kg) of Δ9-tetrahydrocannabinol (THC) upon the behavior of six squirrel monkeys subjected to a Sidman nondiscriminated avoidance schedule that superimposed conditioned stimuli (CS)—unavoidable shock pairings upon the ongoing avoidance behavior. All the animals demonstrated facilitated avoidance response rates and general motor activity during the aversive CS. Oral administration of THC produced avoidance decrements with a consequent increase in the number of shocks received only under the highest dosage (i.e., 12.0 mg/kg). All doses of THC reduced the facilitation of avoidance response rates normally noted during the aversive CS and severely reduced general motor activity. These results were interpreted to suggest that THC may reduce the level of fear normally generated during the presentation of an aversive CS previously associated with unavoidable shock. © 1975, Psychonomic Society, Inc.. All rights reserved.