P300 event-related potentials and cognitive function in social phobia.

The aim of the study was to investigate abnormalities of event-related potentials (ERPs) in social phobia patients indicating deficits in speed and amount of perceptual and cognitive resources as well as relationships between ERPs and cognitive functioning. ERPs were recorded from 19 EEG leads in a two-tone oddball paradigm in medication-free patients with DSM-IV social phobia (n=25) and in age- and sex-matched healthy controls (HC). Neuropsychological test performance was administered. Compared with the HC group, patients with social phobia showed reductions in N1 at temporal leads, N2 and P300 amplitudes, predominantly centroparietally, and longer P300 latencies. The observed P300 latency prolongation was associated with reduced Non-Verbal Learning Test (NVLT) but not the Wisconsin Card Sorting Test (WCST) scores. The reduction in N1 amplitude indicates an impairment in perceptual processing. The reduced P300 amplitudes may reflect reduced cognitive resources for the evaluation of relevant information. The increased P300 latency, indicating longer stimulus evaluation time, was correlated to deficits in learning processes as measured by the Non-Verbal Learning Test but not to executive function as measured by the Wisconsin Card Sorting Test. It may therefore be concluded that social phobia patients show deficits in cognitive information processing as reflected by ERPs.