Information processing and attentional functioning in the developmental course of schizophrenic disorders.

This article examines the evidence that certain deficits in information processing and attentional functioning are present across populations at risk for schizophrenic disorder, with active schizophrenic psychotic symptomatology, and in relative remission after a schizophrenic psychosis. In addition, the evidence that some deficits in processing information occur only in the actively psychotic period is inspected. Deficits in vigilance tasks with high-processing loads, in forced-choice span of apprehension for large arrays, and in serial recall for items that involve active rehearsal occur across risk populations, actively symptomatic schizophrenic patients, and relatively remitted schizophrenic patients. These deficits may reflect vulnerability factors for schizophrenic disorders. Reaction time crossover, dichotic listening, backward masking, and referential communication deficits might also be vulnerability indicators. These deficits may be related to a reduction in the processing capacity that is available for task-relevant cognitive operations in persons vulnerable to schizophrenic disorder, which could, in turn, be caused by several different underlying cognitive anomalies. Cognitive deficits that have been found only during actively psychotic periods or in chronic schizophrenic patients, such as poorer recognition of briefly presented, single, familiar letters or numbers, are characterized by low demands on processing capacity. These deficiencies may be caused by further reduction in available processing capacity or a temporary disruption of automatic as well as attention-demanding processes; they could also reflect a stable, more severe cognitive deficit in a subtype of schizophrenic disorder.