An explanatory model of quality of life in schizophrenia: the role of processing speed and negative symptoms.

Improving the quality of life of patients with schizophrenia is a major goal in managing this devastating disorder, but agreement is lacking about the factors that predict quality of life (QoL) over the course of the disorder.We examined 165 hospitalized patients with schizophrenia in this study. We included measures for psychiatric (PANSS, insight and affective symptoms) and cognitive symptoms. Confirmatory factor analysis established a cognitive structure composed of the following six factors: attention, processing speed, verbal memory, fluency, working memory and executive functioning. Quality of life was assessed using the Heinrichs-Hanlon-Carpenter Scale.Age, duration of illness, presence of more severe negative symptoms and most cognitive factors correlated significantly with QoL indicators. Regression analysis showed that processing speed (PS) was by far the most important cognitive factor that predicted QoL. Moreover, the interaction between PS and negative symptoms, patient age and executive functions modified the effect of PS on QoL. Finally, positive symptoms and other socio-demographic data were not related to QoL in the current study.Our findings suggest that PS and negative symptoms predict QoL in schizophrenia.