The prevalence of depression in bipolar disorder

Bipolar disorder is a recurring, often chronic, illness characterised by periods of mania and depression with variable inter-episode recovery. For the majority of patients it is the depressive component of this illness that contributes to most of the associated morbidity, social disability and mortality. Research and clinical experience suggest that acute treatment and prevention of depressive episodes is by far the most challenging aspect of the care of patients with the disorder. This review examines the contribution of depression to the course and outcome of bipolar disorder as well as diagnostic difficulties that often complicate treatment and may lead to inappropriate medication. Key studies that form the evidence base of treatment recommendation for bipolar depression are presented and areas of therapeutic uncertainty are highlighted. Sophia Frangou is reader in psychiatry and Head of the Section of Neurobiology of Psychosis at the Institute of Psychiatry (PO Box 66, De Crespigny Park, London SE5 8AF, UK. Tel/fax: 020 7848 0903; e-mail: [email protected]). Her research focuses on the pathophysiology and treatment of psychoses. Dr Frangou has received financial support from Sanofi-Synthelabo, GlaxoSmithKline and Bristol-Myers Squibb for conference attendance and consultancies and from AstraZeneca and Novartis for research. 1. The ICD–10 classification of bipolar affective disorder follows a similar subcategorisation based in part on manic or hypomanic episodes (World Health Organization, 1992). Pharmacological treatment of bipolar depression 29 Advances in Psychiatric Treatment (2005), vol. 11. http://apt.rcpsych.org/ major depressive episodes (9%). In a subsequent study, Judd and colleagues focused on bipolar II disorder and obtained weekly symptomatic ratings from 86 patients over a mean period of 13.4 years (Judd et al, 2003). These patients were symptomatic for 53.9% of the time; depressive symptoms predominated, being present for 50.3% of follow-up weeks, whereas manic/hypomanic and cycling/ mixed states were present for 1.3% and 2.3% of the time respectively. As in bipolar I disorder, minor and subsyndromal depression were three times more common than major depressive episodes.