Psychological Medicine cambridge.org/psm Original Article Cite this article: Morton E, Murray G, Michalak EE, Lam RW, Beaulieu S, Sharma V, Cervantes P, Parikh SV, Yatham LN (2018). Quality of life in bipolar disorder: towards a dynamic understanding. Psychological Medicine 48, 1111–1118. https://doi.org/10.1017/ S0033291717002495 Received: 11 March 2017 Revised: 24 July 2017 Accepted: 3 August 2017 First published online: 18 September 2017 Key words: Bipolar disorder; depression; functioning; mania; quality of life Author for correspondence: G. Murray, Ph.D., E-mail: gwm@swin.edu.au © Cambridge University Press 2017 Quality of life in bipolar disorder: towards a dynamic understanding E. Morton 1 , G. Murray 1 , E. E. Michalak 2 , R. W. Lam 2 , S. Beaulieu 3 , V. Sharma 4 , P. Cervantes 5 , S. V. Parikh 6 and L. N. Yatham 2 1 Faculty of Health, Arts and Design Swinburne University, Melbourne, Australia; 2 Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada; 3 Bipolar Disorders Program, Department of Psychiatry, Douglas Mental Health University Institute, McGill University, Montreal, QC, Canada; 4 Regional Mental Health Care London, London, ON, Canada; 5 Mood Disorders Program, Department of Psychiatry, McGill University Health Center (MUHC), Montreal, Canada and 6 Department of Psychiatry, Toronto Western Hospital, Toronto, ON, Canada Abstract Background. Although quality of life (QoL) is receiving increasing attention in bipolar dis- order (BD) research and practice, little is known about its naturalistic trajectory. The dual aims of this study were to prospectively investigate: (a) the trajectory of QoL under guide- line-driven treatment and (b) the dynamic relationship between mood symptoms and QoL. Methods. In total, 362 patients with BD receiving guideline-driven treatment were prospect- ively followed at 3-month intervals for up to 5 years. Mental (Mental Component Score – MCS) and physical (Physical Component Score – PCS) QoL were measured using the self-report SF-36. Clinician-rated symptom data were recorded for mania and depression. Multilevel modelling was used to analyse MCS and PCS over time, QoL trajectories predicted by time-lagged symptoms, and symptom trajectories predicted by time-lagged QoL. Results. MCS exhibited a positive trajectory, while PCS worsened over time. Investigation of temporal relationships between QoL and symptoms suggested bidirectional effects: earlier depressive symptoms were negatively associated with mental QoL, and earlier manic symp- toms were negatively associated with physical QoL. Importantly, earlier MCS and PCS were both negatively associated with downstream symptoms of mania and depression. Conclusions. The present investigation illustrates real-world outcomes for QoL under guide- line-driven BD treatment: improvements in mental QoL and decrements in physical QoL were observed. The data permitted investigation of dynamic interactions between QoL and symp- toms, generating novel evidence for bidirectional effects and encouraging further research into this important interplay. Investigation of relevant time-varying covariates (e.g. medications) was beyond scope. Future research should investigate possible determinants of QoL and the interplay between symptoms and wellbeing/satisfaction-centric measures of QoL. Bipolar disorder (BD) is a severe mental illness associated with a chronic course and recurring periods of mania and depression, ranked by the World Health Organization as the fifth leading cause of disease burden among mental disorders (Ferrari et al. 2016). Research attention in BD has broadened to include quality of life (QoL) as an important outcome of care alongside symptom management (Murray & Michalak, 2012; Morton et al. 2017), and indeed both patients with BD and clinicians have rated improvements in QoL as the most important out- come in the treatment of BD (Maczka et al. 2009). As a person-centred, recovery-oriented con- struct, QoL has powerful potential to represent consumer interests in research and clinical practice (Murray et al. 2017). Naturalistic, prospective investigations offer the opportunity to investigate trajectories of QoL under real-world treatment regimes and inform our under- standing of its relationship to symptoms of BD. While it is sometimes assumed that absence of mental illness equates to mental wellbeing, the two concepts share only a small portion of variance (Keyes, 2005). Consequently, con- structs such as QoL have emerged as treatment goals in their own right in the care of mental illnesses generally (Basu, 2004) and in BD specifically (Murray & Michalak, 2012; Morton et al. 2017). QoL is prioritised by consumers and thus the personal recovery movement views QoL improvement as an outcome of equal importance to symptom remission (Murray et al. 2017). Popular interest in QoL is paralleled in the scientific BD literature, with publications referencing QoL increasing exponentially over recent years (Murray & Michalak, 2012). These studies show that QoL is impaired in individuals with BD relative to the general population, even during euthymic periods (Brissos et al. 2008; Gutiérrez-Rojas et al. 2008), suggesting that attention needs to be paid to improving this patient-valued outcome. We propose that a critical step towards this goal is to develop under- standing of (a) the impact of current guideline-driven treatment on QoL in BD, and (b) the dynamic relationship between symptoms of BD and QoL: existing relevant literature is briefly reviewed before introducing the present study.