Types of Bipolar Disorder
Bipolar disorder has a number of types, including bipolar I and bipolar II disorder. Depending on how rapidly the mood swings occur, the episodes of bipolar disorder can also be described as having mixed (mood disordered episodes that last less than the usual amount of time required for the diagnosis) features or rapid cycling (four or more mood disordered episodes per year) features. About two-fifths of people with bipolar disorder have at least one period of rapid cycling over the course of their lifetime. For every type and duration of the illness, the sufferer experiences significant problems with his or her functioning at school, at work, socially or otherwise in their community, may need hospitalization, or may have psychotic symptoms (for example, delusions or hallucinations). The diagnosis of bipolar I disorder requires that the individual has at least one manic episode but does not require a history of major depression. Bipolar II disorder is diagnosed if the person has experienced at least one episode of major depression and at least one episode of hypomania (a milder form of mania).