Psychophysiological and subjective indicators of aversive Pavlovian conditioning in generalized social phobia

Background: Aversive conditioning has been proposed as an important etiologic mechanism in social phobia; however, empirical evidence is scarce and has not relied on a detailed analysis of the acquisition and extinction of the conditioned emotional response. Methods: Fourteen men sustaining generalized social phobia and 19 healthy control subjects participated in differential aversive conditioning with two neutral faces as conditioned stimuli and an aversive odor as unconditioned stimulus. Subjective and peripheral physiological responses were obtained. Results: Both groups were successfully conditioned as reflected by differential subjective (valence, arousal, subjective unconditioned stimulus expectancy) and peripheral physiological responses (skin conductance, startle response). There was no evidence for an enhanced conditionability in the social phobics; however, they showed an enhanced unconditioned stimulus expectancy, especially for the nonreinforced conditioned stimuli during acquisition, and a delayed extinction of the conditioned skin conductance response as well as a certain dissociation between subjective and physiological responses. Conclusions: The enhanced unconditioned stimulus expectancy during acquisition and the overall elevated subjective arousal suggest that, under threat, subjects with generalized social phobia may be more prone to associate neutral social cues and an aversive outcome. Furthermore, delayed extinction of the conditioned response seems to contribute to the etiology and maintenance of generalized social phobia.