Behavioral and P3 amplitude enhancement in schizophrenia following feedback training.

In order to clarify the remediability of behavioral and electrophysiological abnormalities in schizophrenia, hit rate, reaction time, and P3 amplitude from auditory event-related potentials were evaluated before and after feedback training of a task in 14 schizophrenics and 12 age-matched normal controls. Although mean changes in the three indices due to the training were nonsignificant in both schizophrenic and normal control groups as a whole, the changes in hit rate and reaction time correlated significantly with the P3 amplitude change in the schizophrenic (r = 0.60 and -0.58, respectively) but not in the normal control group. The P3 amplitude change also correlated with the P3 amplitude before the training only in the schizophrenic group (r = -0.68), suggesting that the training was more effective for the schizophrenic patients with marked P3 amplitude reduction. The observed P3 amplitude increase due to training may represent an electrophysiological correlate of a remediable aspect of behavioral deficits in schizophrenics, which may underlie the effectiveness of nonpharmacological treatments.