Attentional performance in positive- and negative-symptom schizophrenia.

Two tasks designed to measure selective attention were administered to schizophrenics, patients with bipolar disorder, and normal subjects. Schizophrenics were divided into three subgroups: positive-, negative-, and mixed-symptom patients. Positive-symptom schizophrenics showed significant deficits on a digit-span task when compared to normal subjects. Furthermore, the positive group was the only one to show a significant performance decrement in the distraction condition of the digit-span task. There were no significant group differences in performance on a dichotic listening test. The results of the present study are contrary to the hypothesis that selective attention deficits are characteristic of negative-symptom schizophrenia. Instead, the findings suggest that positive symptoms are associated with greater susceptibility to distraction.