Decreased P3 amplitudes elicited by negative facial emotion in manic patients: selective deficits in emotional processing.

Manic patients have impairments in recognizing negative emotional stimuli. However, there have been few studies on manic patients' neurophysiological responses to facial emotions. We measured the P3 event-related potentials using facial emotional stimuli to investigate whether the impairment in recognition of negative emotions is greater in maniac patients. We recruited twenty manic patients and twenty controls. A visual oddball paradigm was used with facial pictures: happy, neutral, sad, fear, and disgust emotions. While P3 amplitudes of emotional stimuli were significantly larger than those of neutral stimuli in controls, the amplitudes were not significantly different from those for neutral pictures in manic patients. Repeated-measures analysis of variance on P3 amplitudes revealed significant interaction effects of paired emotions as sad-neutral, disgust-neutral, fear-neutral, but not in the happy-neutral emotion pairs. These differential P3 responses suggest that manic patients may have abnormal neurophysiological activity when evaluating negative facial emotions. Thus, these findings may give the evidence for reduced negative emotion recognition of manic patients.