Factorial structure of the Manchester Short Assessment of Quality of Life in patients with schizophrenia-spectrum disorders

Abstract

Purpose: Subjective quality of life is a central patient-reported outcome in schizophrenia-spectrum disorders. The Manchester Short Assessment of Quality of Life (MANSA) is an established and widely used instrument for its assessment. The present study is a secondary analysis of large schizophrenia studies and aims to establish the factorial structure of the MANSA with a rigorous two-step methodology. Methods: A sample of 3120 patients was randomly split into two datasets; the first includes two thirds of the patients and serves as the calibration sample (N = 2071) and the second includes one third of them and serves as the validation sample (N = 1049). We performed an exploratory factor analysis with the calibration sample followed by a confirmatory factor analysis with the validation sample. Results: Our results for both samples revealed a model with adequate fit comprising two factors. The first factor encompasses eight items measuring satisfaction with a variety of life and health-related aspects of quality of life, whereas the second consists of four items assessing satisfaction with living environment comprising living alone or with others, accommodation, family, and safety. These two factors correlate in a different way with socio-demographic characteristics such as age and living conditions. Conclusions: Future trials and service evaluation projects using the MANSA to measure quality of life should take into account that satisfaction with living environment may be distinct from satisfaction with other life and health-related aspects of quality of life.