Cognitive functioning and negative symptoms in first episode schizophrenia: different patterns of correlates.

Negative symptoms of schizophrenia have been related to disturbances of executive functions, memory, attention and motor functioning. The executive functions dimension comprises a variety of cognitive subprocesses, including speed of processing, flexibility and working memory. We independently analysed the relationship between different cognitive tasks and clinical symptoms (negative, positive and disorganized) in a sample of 126 first-episode patients with schizophrenia spectrum disorders. Negative symptoms were significantly associated with performance on executive-functions and motor coordination tasks. Within the executive functions domain only those tests that required speeded performance showed a significant association with the negative dimension. The widely described relationship between negative symptoms and executive impairments in schizophrenia appears to be mediated by likely dysfunctions in the speed of processing instead of by working memory impairment.