What does quality of life refer to in bipolar disorders research? A systematic review of the construct's definition, usage and measurement

Background: Quality of life (QoL) is increasingly investigated in bipolar disorders (BD) research, yet little attention has been paid to its optimal definition and measurement. This is a significant limitation, as the broader QoL literature recognises a number of divergent meanings and measurement tensions. The aim here was to advance understanding of QoL in BD by clarifying use of the construct in the existing literature and considering measurement implications. Methods: Thematic analysis techniques were used to interrogate articles identified via systematic search for (a) explicit discussion of QoL definitional/measurement issues, and (b) usage of the term QoL. Results: A total of 275 articles were included in the analysis. A range of definitional and methodological issues confounding the study of QoL in BD were identified. While explicit definition of QoL proved rare, thematic analysis of usage of the construct revealed the concepts of functioning, health, subjective experience and wellbeing were thought to be relevant to QoL in BD. Limitations: The review does not engage in top-down theory development. Our analysis was grounded in the empirical literature to support future theoretical work relevant to existing usage of QoL in BD. Conclusions: There was no evidence of a consensus definition of QoL in BD. A plurality of QoL definitions is not necessarily a flaw in the literature, but points to empirical and conceptual issues demanding attention. Awareness of the diversity of constructs associated with QoL will enable clinicians to better select treatments on the basis of specific QoL outcomes. A research agenda and provisional considerations for empirical research are outlined based on the present analyses.