Bipolar disorder.

Manic-depression disorder, also known as bipolar disorder, is a severe mental disorder involving manic episodes that are usually accompanied by episodes of depression. It is a chronic mental disease that affects over two million adults in the United States, which is about one percent of the population over the age of eighteen. Symptoms of the disorder often appear in adolescence or early adulthood, although it can sometimes start in early childhood or as late as …

…set off more frequent cycles. In Rapid Cycling Bipolar Disorder, or Cyclothymic Disorder, a person has at least four episodes per year, in any combination of manic, hypomanic, mixed, or depressive episodes. This course pattern is seen in approximately five to fifteen percent of patients with bipolar disorder. It sometimes results from taking too many antidepressants (as often happens with people who have Bipolar II Disorder), which may trigger a high, followed by a crash.