Bipolar disorder consists of three subsets: Bipolar I, Bipolar II, and Cyclothymia. Bipolar I involves severe mood swings that significantly impair functioning, while Bipolar II is a milder form with less severe episodes. Cyclothymia is the mildest form with milder highs and lows. The causes of bipolar disorder are believed to include biological, neurochemical, genetic, and environmental factors. Treatments include psychotherapy, medication, and sometimes hospitalization. Common medications are mood stabilizers, anticonvulsants, antidepressants, and antipsychotics.