DIFFERENTIAL RELATIONSHIPS BETWEEN POSITIVE AND NEGATIVE SYMPTOMS ANDNEUROPSYCHOLOGICAL DEFICITS IN SCHIZOPHRENIA

This study assessed the relationships between positive and negative cl inical symptoms and specific neuropsychological deficits in a group of stable schizophrenic patients, Method Thirty patients were assessed u sing the Positive and Negative Syndrome Scale (PANSS) for schizophreni a and a battery of cognitive tests. The PANSS assessments were done by a group of raters blind to the results of cognitive tests, while the cognitive tests were conducted by a different group of raters who rema ined blind to the PANSS scores. Results: We found that, although posit ive and negative symptoms showed a trend toward direct correlation wit h each other, they correlated with distinct cognitive deficits. Patien ts with higher negative scores had more perseverative responses, perse verative errors, and completed fewer categories on the Wisconsin Card Sorting Test; they also experienced more difficulties on trail making and verbal fluency tests. On the other hand, positive symptoms were as sociated with poor performance on the Digit Span, particularly the Dig it Span Forward. Conclusions: Our findings are in agreement with previ ous reports that negative symptoms may be associated with poor perform ance on cognitive tests reflecting particularly frontal function. Posi tive symptoms, on the other hand, seem to be associated with poor atte ntion, specifically of auditory type, and thus, possibly with dysfunct ion within the more widespread neural networks underlying attention. O ur findings support the hypothesis that positive and negative symptoms may be associated with distinct neuropsychological deficits and thus with distinct neurological substrates and point to the need to address both positive and negative dimensions when studying schizophrenia.