Fear conditioning and extinction in pediatric obsessive-compulsive disorder.

ABSTRACT

BACKGROUND: Fear acquisition and extinction are central constructs in the cognitive-behavioral model of obsessive-compulsive disorder (OCD), which underlies exposure-based cognitive-behavioral therapy. Youths with OCD may have impairments in fear acquisition and extinction that carry treatment implications. METHODS: Eighty youths (39 OCD, 41 healthy controls [HC]) completed clinical interviews, rating scales, and a differential conditioning task that included habituation, acquisition, and extinction phases. Skin conductance response (SCR) served as the primary dependent measure. RESULTS: During habituation, participants with OCD exhibited a stronger orienting SCR to initial stimuli relative to HC participants. During acquisition, differential fear conditioning was observed for both groups as evidenced by larger SCRs to the visual conditioned stimulus paired with an aversive unconditioned stimulus (CS+) compared with a CS-; OCD participants exhibited a larger SCR to the CS+ relative to HC participants. The absolute magnitude of the unconditioned fear response was significantly larger in participants with OCD, compared with HC participants. During extinction, OCD participants continued to exhibit a differential SCR to the CS+ and CS-, whereas HC participants exhibited diminished SCR to both stimuli. CONCLUSIONS: Participants with OCD exhibit a different pattern of fear extinction relative to HC participants, suggestive of greater fear acquisition and impaired inhibitory learning.