Cognitive factors in schizophrenia: causes, impact, and treatment.

Greater attention has been given to the cognitive dimension in schizophrenia in recent years. This has resulted from increased recognition that cognitive impairment and negative symptoms of the disease have a greater impact on quality of life (QOL) compared to positive symptoms. Successful treatment of positive symptoms in patients with schizophrenia has not been shown to robustly translate into improvements in employment status or social relationships, while cognitive improvements are strongly associated with these important aspects of QOL and independence. These findings are based on extensive testing with standard cognitive tests for measuring executive function, verbal learning and memory, word recall, verbal working memory, spatial working memory, attention, and vigilance. Verbal learning and executive function, in particular, have been found to be valid predictors of employment success independent of the degree of severity of positive symptoms.