Overview of bipolar disorder

Bipolar disorder is characterised by distinct episodes of mania or hypomania, and depression—see Features of bipolar disorder.

The lifetime prevalence is approximately 0.6% for bipolar I disorder and 0.4% for bipolar II disorder. Bipolar disorder can reduce a person’s life expectancy by approximately 10 years (mainly due to cardiovascular disease, respiratory illnesses, diabetes, and suicide), and affect their relationships, career and self-esteem. The risk of suicide is significant (up to 30 times greater than the general population), particularly during a depressive episode, or in patients with mixed features or rapid cycling bipolar disorder.

Bipolar disorder has a strong genetic basis and a peak onset in young people. Bipolar II disorder is more common in females, whereas the incidence of bipolar I disorder is the same in males and females.