Bipolar disorder is an illness where a person experiences extreme changes in mood, thought, energy and behavior. He may feel manic for an instant and depressed the next.

In manic episodes, there is a distinct period of abnormally elevated or irritable mood lasting at least one week. During that time, the person experiences three or more of the following symptoms: grandiosity, decreased need for sleep, pressure to keep talking, flight of ideas, distractibility, increase in goal-oriented activity and excessive involvement in pleasurable activities that have a high potential for painful consequences. A manic person can be reckless and impulsive. He is very self-confident and optimistic. In severe cases, a manic person may even have delusions and hallucinations.

In a hypomanic episode, there is a distinct period of persistently elevated or irritable mood different from the usual nondepressed mood lasting for four days or more. During the mood disturbance, the person experiences three or more of the symptoms of mania. The disturbance in mood must be observable by others but not so severe as to impair his occupational functioning and social activities.

In a major depressive episode, a person feels a depressed mood and/or loss of interest or pleasure for two weeks or more. Five or more of the following symptoms may be experienced by the person most of the day almost everyday, such as depressed mood, markedly decreased interest or pleasure in activities, significant weight loss or weight gain, insomnia or hypersomnia, psychomotor agitation or retardation, fatigue or loss of energy, feelings of worthlessness or guilt, diminished ability to think or concentrate and recurrent thoughts of death. The symptoms can cause significant distress or impairment in social and occupational functioning. The depressed person may have difficulty in crying, have countless unprovoked crying spells or he may just be indifferent. He may also complain of aches and pains that may have no real physical causes.