Burden of bipolar depression: Impact of disorder and medications on quality of life

Bipolar disorder is a complex, chronic psychiatric condition characterized by recurring episodes of depressive illness and mania or hypomania. Although the manic or hypomanic episodes define the disorder, recent research has shown that depressive symptoms predominate over manic symptoms in the majority of patients, and that bipolar depression accounts for much of the significant morbidity and mortality associated with bipolar disorder. Given these findings, there has been a recent upsurge of interest in furthering our understanding of the burden of depression in bipolar disorder. At the same time, increasing scientific attention is now being paid to expanding the measurement of outcome in bipolar disorder to encompass broader indicators of response, one of which is the assessment of quality of life (QOL). In this review, we provide a summary of the current knowledge about QOL in the depressive phase of bipolar disorder, and the effects of pharmacological treatment interventions for bipolar disorder upon QOL. It appears that QOL is poorer in bipolar disorder than in other mood disorders and anxiety disorders, but that schizophrenia might compromise QOL more severely than bipolar disorder. Existing data also suggest that, for patients with bipolar disorder, QOL is negatively associated with depression, both as a cross-sectional mood state and perhaps also as a feature of the patient's course. Despite its clinical and public health importance, bipolar depression has only recently started to receive the attention it warrants in clinical trials, and many important questions about its optimal pharmacological management remain to be answered. There is also a paucity of information about the impact of pharmacological interventions on QOL in bipolar depression. To our knowledge, only two clinical trials to date have specifically examined the impact of medications on QOL in patients with bipolar depression. A small number of other studies have examined the effects of depressive symptoms on QOL in patients who are experiencing manic or mixed episodes. Nonetheless, QOL appears to be a meaningful and important indicator of outcome and recovery in this patient population, and one that warrants further scientific interest and energy.