Depression and subjective quality of life in chronic phase schizophrenic patients

Objective: To evaluate the influence of depression on subjective quality of life in schizophrenic patients. Method: Sixty-seven schizophrenic patients in a stabilized phase were included. Schizophrenic symptoms were evaluated using the Positive and Negative Symptoms Scale (PANSS). The subjective quality of life was evaluated using the short version of the Lehman quality of life scale (QoLI). Depression was evaluated using the Calgary Depression Scale for Schizophrenia (CDSS) and extrapyramidal effects with the Extrapyramidal Symptoms Rating Scale (ESRS). Results: The PANSS total score, PANSS general psychopathology subscore, PANSS depression factor, the total CDSS and some ESRS scores were negatively correlated with the overall life satisfaction score. The CDSS score was negatively correlated with all except one QoLI score. QoLI scores were significantly lower in depressed patients, and this result remained consistent for four QoLi dimensions when adjusted on ESRS and PANSS scores. When analysing the association between high depression scores and high parkinsonism scores with reduced quality of life, multivariate analysis showed that depression was the main explanatory factor: the CDSS total score explained 22% of the variance of the overall subjective quality of life score. The patient questionnaire at the ESRS explained 10.5% of the variance of the 'mental and physical health' QoLI score. Conclusion: In schizophrenic patients, depressive symptoms should be focused because of their strong association to overall subjective quality of life.