To examine the relative contributions of psychiatric symptoms, functional disability, neuropsychological functioning and sociodemographic variables to quality of life (QOL) in patients with chronic schizophrenia.

We examined 165 hospitalised patients with long term schizophrenia (DSM-IV). Measures of psychiatric symptoms included depression (Calgary depression Scale), insight (David Insight Scale), symptom severity (BPRS) and PANSS (Positive and Negative Symptom Scale). Neuropsychological battery included tests for verbal memory, executive functioning, verbal fluency, working memory, motor speed and processing speed. Functional disability was assessed with the Disability Assessment Schedule (DAS-WHO) and Quality of life was assessed with the Quality of Life Scale.

Age, years of evolution, negative symptoms, insight and neuropsychological variables (except motor speed) all were significantly related to level of quality of life. in a multiple regression analysis, entering the neuropsychological functioning, functional disability and negative symptoms generated a model which accounted for a 74.9% of the variance in QOL. Functional disability, as expected, accounted for 56% of the variance, whereas Processing Speed explained an additional 6.2%. Symptom Severity and Verbal Fluency predicted 3.7% and 3.5% of the variance, respectively. Negative symptoms, Verbal Memory and Vocabulary, were also significant predictors in the model, but had less predictive value. However, Positive Symptoms and Sociodemographic Variables did not significantly contribute to predict quality of life.

Our findings support the predictive value of neuropsychological functioning, functional disability and severity of negative symptoms in long term quality of life in schizophrenia.