Does negative symptom change relate to neurocognitive change in schizophrenia? Implications for targeted treatments

Abstract 

Negative symptoms and cognitive dysfunction are among the most challenging obstacles in the treatment of schizophrenia. It is unknown to what extent they are overlapping or independent disease processes. In the search for targeted treatments of negative symptoms and cognitive impairments, it is imperative to determine their longitudinal relationship. 267 stable outpatients with schizophrenia in a work and cognitive rehabilitation program were evaluated using symptom measures and a comprehensive neuropsychological test battery at baseline and at the conclusion of rehabilitation, 6 months later. Baseline negative symptom, neuropsychological variables and change scores from intake to follow-up on these variables were correlated. These analyses were repeated with a subsample (n=161) who had clinically significant negative symptoms at baseline. ANCOVA's were performed to compare patients whose negative symptoms improved by 5 points or more (n=69) with those whose negative symptoms got worse by 5 points or more (n=26) on their neurocognitive performance at follow-up. Intake negative symptoms were significantly associated with theory of mind and visuomotor processing. Results failed to support a lawful relationship between change in negative symptoms and neurocognition. These findings suggest that negative symptoms and neurocognition should be viewed as relatively independent targets for intervention.

Keywords: Schizophrenia, Negative symptoms, Neuropsychological tests, Longitudinal relationship, Theory of mind