Neurocognitive correlates of positive and negative syndromes in schizophrenia

To identify the neurocognitive correlates of positive and negative schizophrenic syndromes using a battery of information-processing measures as the principal method of evaluation.

Fifty-two treated, symptomatically stable, schizophrenic (DSM-III-R) patients and 24 age-matched, healthy volunteers were administered a computerized cognitive test battery (COGLAB). The battery included measures of preattentional, attentional, conceptual, and psychomotor performance. The patients' psychopathology was rated with the positive and negative syndromes scale (PANSS), which derived scores for positive symptoms, negative symptoms, general psychopathology, and insight.

Compared with controls, schizophrenic patients, as a group, showed significant deficits on all of the neurocognitive tasks. Impaired performance on the backward masking, span of apprehension, and Wisconsin card sorting tasks correlated significantly with negative symptoms (r = 0.27-0.40), general psychopathology (r = 0.29-0.42) and impaired insight (r = 0.34-0.52), but no clear association was found between positive symptom scores and neurocognitive deficits.

Schizophrenic patients with predominantly negative symptoms and impaired insight seem to exhibit more severe neurocognitive deficits, which lends support to the evolving concept of schizophrenia subtypes and their distinctive neurobiological mechanisms.