Predictors of quality of life in type 2 diabetes patients with schizophrenia, major mood disorder, and without mental illness

Purpose: The aim of the current study is to compare the predictors of health-related quality of life in individuals with schizophrenia, major mood disorder, and no mental illness, all with type 2 diabetes. Methods: A total of 100 individuals with schizophrenia, 101 with a major mood disorder, and 99 without mental illness, all with type 2 diabetes, rated their health-related quality of life on the Medical Outcomes Survey, Short Form-12; physical and mental composite scores (PCS and MCS) were calculated. We performed a hierarchical multiple regression on PCS and MCS in each sample starting with a basic set of predictors and then adding diabetesrelated variables. We compared the regression weights and incremental variance explained within each group. Results: The number of co-occurring medical conditions was significantly associated with lower PCS in all three groups and with lower MCS in the no mental illness group. Diabetes-related variables added significant incremental variance to the prediction of PCS in the no mental illness group but not in either psychiatric group. Conclusions: For persons with diabetes and mental illness, as well as with no mental illness, additional medical conditions exert a strong effect on physical well-being. The impact on quality of life of diabetes-related factors may be lower in persons with diabetes and serious mental illness compared to those with diabetes and no mental illness.