Aim: In recent years, greater attention has been given to quality of life (QOL) in schizophrenia and several studies reported that negative and depressive symptoms and cognitive dysfunction are related to patient QOL. But because a variety of QOL measures have been used in the previous studies, there seems to be no unanimous predictors for subjective and objective QOL. The purpose of the present study was to elucidate the relationship between clinical variables and subjective and objective QOL in outpatients with schizophrenia, using schizophrenia disease-specific QOL measures. Particular attention was paid to cognitive function as a predictor of QOL.
Methods: Schizophrenia symptoms of the Positive and Negative Syndrome Scale (PANSS) were divided into five factors: positive factor, negative factor, cognitive factor, emotional discomfort, and hostility. The study sample consisted of 84 schizophrenia outpatients. Subjective and objective QOL were assessed with Schizophrenia Quality of Life Scale (SQLS) and the Quality of Life Scale (QLS), respectively.
Results: Subjective QOL correlated significantly with emotional discomfort, positive factor, negative factor, extrapyramidal symptoms and cognitive factor, while objective QOL correlated with negative factor, cognitive factor, emotional discomfort, extrapyramidal symptoms, and dose of antipsychotics. Total score and three of four subscales in the QLS correlated significantly with cognitive factor, while cognitive factor had a significant correlation with only one of three scales of SQLS. Stepwise regression showed that subjective QOL was significantly predicted by emotional discomfort and extrapyramidal symptoms, while negative factor was the most important predictor of objective QOL.
Conclusion: Cognitive dysfunction had a greater influence on objective QOL than subjective QOL. Treating depressive and negative symptoms and extrapyramidal symptoms might contribute to enhanced subjective and objective QOL.