Electrophysiological investigation of long-term threat discrimination learning in social anxiety disorder

Fear extinction deficits and spread of fear to benign stimuli are thought to be key factors in social anxiety disorder (SAD), potentially explaining how fear generalizes to various social situations. The late positive potential (LPP) is an event-related potential component that is sensitive to altered emotional processing in anxiety and fear-related disorders. In SAD, (1) the influence of fear conditioning on the LPP and (2) conditioning, extinction and recall using disorder-relevant stimuli have hardly been studied so far.

Participants with social anxiety disorder (SAD, n = 33), panic disorder (PD, n = 31), and a healthy control group (CG, n = 31) underwent a two-day differential fear conditioning paradigm using faces as conditioned stimuli. The paradigm included fear acquisition and extinction, followed by a recall phase 24h later. Self-reports, skin conductance responses (SCRs), heart period (HP) changes, and the LPP were assessed.

Over the course of acquisition, the SAD group, but not the PD and CG groups, partially failed to discriminate between the CS+ and CS‒. This discrimination deficit was most evident in the LPP and remained during day 2 recall.

While group differences are - if anything - rather subtle, a lack of discrimination between neutral and aversive conditioned social stimuli appears mostly associated with social anxiety. Fear discrimination deficits in SAD participants were especially evident in alterations of the LPP over the course of learning. These results underscore the potential role of deficits in fear discrimination during the consolidation of social learning experiences, which is particularly relevant for the development of SAD.