Positive and negative schizophrenic symptoms, attention, and information processing.

This study was concerned with the relationship between attentional and information-processing deficits and positive vs. negative symptoms in schizophrenia. Sixteen schizophrenic patients, rated for extent of positive and negative symptomatology, 17 depressed patients, and 31 normal control subjects were tested on a measure of distractibility and ability to process under information overload. To establish the validity of our measures, schizophrenic patients were compared with depressed patients and with normal control subjects. Lowered processing capacity appeared to be specific to schizophrenia, although the specificity of differential distractibility was less clear. For schizophrenic patients, positive symptoms were related to distractibility, whereas negative symptoms were associated with lowered processing capacity. These findings were interpreted as supporting Crow's (1981) hypothesis that the two clinical syndromes reflect independent pathological processes.