Body mass index and quality of life among outpatients with schizophrenia in Japan

Background: Obesity is becoming more prevalent and thus growing as a public health concern in patients with schizophrenia. This investigation evaluated the relationship between body weight and the self-reported quality of life (QOL) of Japanese patients with schizophrenia. Methods: We recruited outpatients (n=225) aged 42.5 +/- 12.8 (mean +/- SD) years with a DSM-IV diagnosis of schizophrenia who were admitted to psychiatric hospitals. This study used a cross-sectional design. The assessments included an interview to obtain sociodemographic data, the second version of the Short Form Health Survey (SF-36v2), the 10-item version of the Drug Attitude Inventory (DAI-10), the Clinical Global Impression-Severity (CGI-S) and height and weight measurements. SF-36v2 subscores were examined for differences based on the following body mass index (BMI) categories: healthy weight (BMI < 24.9), overweight (BMI 25-29.9) and obese (BMI > 30). A multiple regression analysis was employed to assess the relationship between these BMI categories and QOL outcomes. Results: The overall prevalence of obesity in our sample was 16.4%. A multiple regression model revealed that age, gender, DAI-10 scores, CGI-S scores, social functioning, role emotional functioning, mental health, and Mental Composite Summary (MCS) score were significantly and positively associated with overweight status. Physical functioning, general health, role emotional functioning, mental health, and a physical composite summary (PCS) score were significantly and negatively associated with obesity. Conclusions: The burden of obesity is both a physical and a mental problem. An obesity intervention program for patients with schizophrenia may improve health-related QOL in patients with schizophrenia.