OBJECTIVES: To determine the epidemiological, clinical, and economic burden of bipolar disorder (BD) in Europe. METHODS: A systematic review of publications from the last 10 years relating to the burden of bipolar disorder was conducted, including studies on epidemiology, patient-related issues, and costs. RESULTS: Data from the UK, Germany, and Italy indicated a prevalence of bipolar disorder of ~1%, and a misdiagnosis rate of 70% from Spain. In one study, up to 75% of patients had at least one DSM-IV comorbidity, commonly anxiety disorders and substance/alcohol abuse. Attempted suicide rates varied between 21-54%, with 18% mortality in the UK. The chronicity of bipolar disorder exerted a profound and debilitating effect on the patient. Only 30% of German patients were employed full time at a level matching their qualifications. In Italy, 63-67% of patients were unemployed and in Germany, 72% received disability payments. In the UK, the annual costs of unemployment and suicide were £1510 million and £179 million, respectively. The estimated UK national cost of bipolar disorder was €4.59 billion, with hospitalization during acute episodes representing the largest component. CONCLUSIONS: Bipolar disorder is a major and underestimated health problem in Europe. A number of issues impact on the burden of the disease, such as comorbidities, suicide, early death, unemployment or underemployment. Direct costs of bipolar disorder are mainly associated with hospitalization during acute episodes. Indirect costs are a major contributor to the disease burden but are not always recognized in research studies.Supported by funding from AstraZeneca Pharmaceuticals LP.