The effects of clinical illness severity and physical activity on health-related quality of life in schizophrenia

Background: Quality of life is an important clinical outcome in individuals with schizophrenia. Illness severity and physical activity (PA) were independently reported to influence health-related quality of life (HRQoL) in people with schizophrenia. This study attempts to examine the intensity and types of PA and their impact on HRQoL, as well as the relative contributions of illness severity, PA, and sedentary behavior (SB) to HRQoL in people with schizophrenia. Methods:Demographic information was collected from 297 community-dwelling individuals with schizophrenia. Severity of illness was assessed on the Clinical Global Impression—Severity (CGI-S); PA and SB were assessed on the Global Physical Activity Questionnaire (GPAQ); HRQoL was assessed on the RAND-36. Regression analyses were conducted to examine the impact of different types and intensities of PA on HRQoL, and the relative impact of CGI-S, GPAQ-PA, and GPAQ-SB on HRQoL. Results: Most participants had low PA level, and travel is the main type of PA adopted. Leisure time, travel-related, work-related, moderate-, and vigorous-intensity PA were all not associated with HRQoL. Lower severity of illness was significantly associated with better physical (PHC), mental (MHC) and global (GHC) health composites of the RAND-36 (GHC: t = − 5.628, p < 0.001, PHC: t = − 4.026, p < 0.001, MHC: t = − 5.534, p < 0.001). Both PA and SB were not significantly associated with PHC, MHC, and GHC. Conclusion: Severity of illness has a significant impact on HRQoL in people with schizophrenia. However, we found no evidence to support the association between physical activity and sedentary behavior with HRQoL.Ministry of Health (MOH)National Medical Research Council (NMRC)Accepted versionThis study is supported by the National Medical Research Council Clinician Investigator Salary support Programme under the National Medical Research Council Translational and Clinical Research Flagship Programme (Grant No.: NMRC/CISSP/2010/002). Ms. Ang is supported by the Singapore Ministry of Health’s National Medical Research Council under the Centre Grant Programme (Grant No.: NMRC/CG/004/2013)