Bipolar disorder or manic depression is a psychological illness which manifests as having extreme changes in mood, behavior and thought. A persons mood can change from mania to depression in a short period of time. These mood swings from highs to lows can last for hours, days, weeks, or months. A person with this mood disorder has a unique pattern of mood fluctuations specific to him but once his pattern is analyzed, it can be quite foreseeable.

Bipolar disorder usually starts in late adolescence or early adulthood but it can also start in early childhood or late adulthood. Recent studies show a genetic factor to this illness. It affects men and women equally although their initial manifestations of the disorder may differ (men start with a manic episode while women with a depressive episode). The disorder can be found in all races and social classes. It continues throughout life. Because the symptoms are episodic, one may not be diagnosed correctly. Thus, those who have the illness may not be treated early. Once properly diagnosed, however, the illness can be treated.

Bipolar disorder is associated with four general types of mood episodes. A manic episode is characterized by a persistently elevated mood for at least one week. A hypomanic episode is a milder type of mania which last for four days or more. A major depressive episode is characterized by a loss of interest or pleasure lasting for two weeks or more. A mixed episode is where an individual experiences mood swings of mania and depression almost every day for at least one week.

Bipolar I disorder is a syndrome where a complete set of mania symptoms (e.g. at least one week of elevated mood, grandiosity, decreased need for sleep, more talkativeness, flight of ideas, distractibility, psychomotor agitation and/or excessive involvement in pleasurable activities where the mood disturbance is severe enough to impair occupational functioning or social activities) not caused by antidepressant medications occurs during the course of the disorder. Bipolar I disorder can be further subdivided into Bipolar I, Single Manic Episode and Bipolar I, Recurrent.

Bipolar II disorder is characterized by occurrence of depressive episodes with at least one hypomanic episode. A hypomanic episode is characterized by an elevated mood different from the usual nondepressed mood lasting for four days. The person experiences the same symptoms as a manic person but these are not so severe as to impair his occupational functioning and social activities.