title: Confirmatory factor analysis of the quality of life scale and new proposed factor structure for the quality of life scale-revised.
abstract: The Quality of Life Scale (QLS) is a frequently used semistructured interview for the assessment of functional outcomes in schizophrenia. Despite the use of the QLS for over 30years, the original 4-factor structure of the instrument (Interpersonal Relations, Instrumental Role, Intrapsychic Foundations, and Common Objects and Activities) has not been rigorously examined. Exploratory factor analyses (EFAs) and confirmatory factor analyses (CFAs) were used to evaluate the factor structure of the QLS in two independent datasets, including a mixed diagnostic sample of multi-episode participants (N=247), and a sample of individuals with a first episode of psychosis (N=337). A CFA with the first dataset indicated a poor fit for the 4-factor model of the QLS. Subsequent EFAs on this dataset led to a more promising 3-factor solution including 16/21 of the QLS items, which were similar to the first 3 of 4 factors originally proposed for the QLS. CFAs on the same dataset indicated that the 3-factor model for the QLS-Revised (QLS-R) fit the data well. This factor structure was evaluated with the second dataset using CFA and was also found to be fit the data well. The results support the robustness of the 3-factor model of the QLS-R in schizophrenia and mixed diagnostic samples. Future research should evaluate the validity of the 3-factor model of the QLS-R, and consider the merits of changing the name of the Intrapsychic Foundations factor to Motivation.
authors.affiliation: Center for Psychiatric Rehabilitation, Departments of Occupational Therapy, Psychology, and Psychiatry, Boston University, Boston, MA, USA. Electronic address: mueser@bu.edu.
authors.forename: Kim T
authors.initials: KT
authors.lastname: Mueser
authors.affiliation: Center for Psychiatric Rehabilitation, Boston University, Boston, MA, USA.
authors.forename: Min
authors.initials: M
authors.lastname: Kim
authors.affiliation: Department of Psychiatry, University of Calgary, Calgary, Canada.
authors.forename: Jean
authors.initials: J
authors.lastname: Addington
authors.affiliation: Center for Psychiatric Rehabilitation, Departments of Occupational Therapy, Psychology, and Psychiatry, Boston University, Boston, MA, USA.
authors.forename: Susan R
authors.initials: SR
authors.lastname: McGurk
authors.affiliation: Department of Psychiatry, the Geisel School of Medicine at Dartmouth, Hanover, NH, USA; the Dartmouth Institute for Health Policy and Clinical Practice, Dartmouth College, Hanover, NH, USA.
authors.forename: Sarah I
authors.initials: SI
authors.lastname: Pratt
authors.affiliation: Department of Psychiatry, University of Calgary, Calgary, Canada.
authors.forename: Donald E
authors.initials: DE
authors.lastname: Addington
mesh_terms: D005163:Factor Analysis, Statistical; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007406:Interview, Psychological; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011788:Quality of Life; D012559:Schizophrenia / Q000175:diagnosis* / Q000628:therapy; D012565:Schizophrenic Psychology; D055815:Young Adult
keywords: Confirmatory factor analysis; Exploratory factor analysis; Psychosocial functioning; Quality of life scale; Recovery; Structural equation modeling