Cognitive function in schizophrenia: association with negative and positive symptoms

20 schizophrenic patients were classified as having either predominantly negative (n = 11) or predominantly positive symptoms (n = 9), utilizing the Scale for the Assessment of Negative Symptoms and the Scale for the Assessment of Positive Symptoms. Cognitive functioning was evaluated in these participants and 10 nonpatient controls using a word-fluency test and word-generation task. Finally, all participants were evaluated using the Coglab Card Sort Test, a computerized version of the Wisconsin Card Sort Test. The only reliable difference in performance among groups was on perseverative errors on the Coglab Card Sort Test. Schizophrenic participants made significantly more perseverative errors than controls and those classified as having primarily negative symptoms made more perseverative errors than those classified as having predominantly positive symptoms. These findings confirm previous reports with respect to cognitive functioning of schizophrenic patients and are consistent with the hypotheses regarding frontal lobe dysfunction in schizophrenia. These data encourage research with larger samples.