Manic depression, or bipolar disorder, is a type of mood disorder that goes beyond the day's ordinary ups and downs. It is characterized by periodic episodes of extreme elation, elevated mood, or irritability countered by periodic classic depressive symptoms.

It is a condition in which people have mood swings that are far beyond what most people experience in the course of their lives. These mood swings may be low, as in depression, or high, as in periods when one feels very elated. These high periods are known as "manic" phases. Many sufferers have both high and low phases, but some will only experience either depression or mania.

It is not related to substance abuse, and includes a number of disturbances in behavior and thinking that results in significant life adjustment problems. This usually occurs in stages where at one end there is severe depression, which turns into moderate depression; then becomes the mild and brief mood disturbances that many people call "the blues," then normal mood returns, then hypomania, and then mania.

Along a continuum it can be described as:

Normal state of happiness, pleasure, joy

Moderate elations of hypomanic or Cyclothymic personality, with heightened self-esteem, increased creativity and work ability, decreased need for sleep

Mania stage wherein disturbances in social and physiological functions takes place and

Delirious or psychotic Mania stage consisting of severe overactivity, hostile attitude, destruction of property, violent behavior, paranoid delusions and hallucinations.

These manic episodes are characterized by extreme irritability and distractibility, excessive euphoric feelings, sustained periods of unusual behavior with significant risk-taking, increased energy, activity, rapid talking and thinking, agitation, decreased sleep, poor judgment, increased or decreased sex drive, substance abuse, provocative or obnoxious behavior, and denial of the problem.

The course of the illness varies from patient to patient. Without treatment, the frequency and severity of this recurring illness can increase over the years.