Psychometric properties of the forensic inpatient quality of life questionnaire: quality of life assessment for long-term forensic psychiatric care

A substantial group of forensic psychiatric patients require (life)long forensic psychiatric care. Instead of aiming at re-entry into society, treatment in long-term forensic psychiatric care (LFPC) is principally aimed at medical and psychiatric care and optimising quality of life (QoL). To assess QoL in LFPC, the influence of both the mental disorder and the restrictive context should be considered. Therefore, a new instrument was developed: the Forensic inpatient QoL questionnaire (FQL). The FQL is based on the results of concept-mapping with patients and staff within LFPC. The main purpose of this study is to evaluate the psychometric properties of the FQL. One hundred and sixty-three FQLs, filled out by 98 male long-term forensic psychiatric patients, were included for testing reliability and content validity. For testing construct validity, 53 patients additionally completed the World Health Organisation Quality of Life-Brief version and 50 of them the Affect Balance Scale. Outcomes indicate that the FQL has good psychometric properties. Fifteen of the 16 FQL domains showed adequate to good reliability (Cronbach's α range .69–.91) and 9 domains met the criteria for homogeneity. Content validity was demonstrated by exploratory factor analysis, which revealed a three-factor structure: social well-being, physical well-being and leave. Construct validity was supported by 59% correctly hypothesised inter- and intrascale Pearson's correlation coefficients. Good psychometric properties and its clinical-based development make the FQL a valid and useful instrument for QoL assessment in LFPC. The FQL could therefore contribute to evidence-based and more advanced treatment programmes in LFPC.