Definition of Bipolar disorder :

Bipolar disorder is a condition in which people go back and forth between periods of a very good or irritable mood and depression. The "mood swings" between mania and depression can be very quick.

Causes, incidence, and risk factors:

Bipolar disorder affects men and women equally. It usually starts between ages 15 - 25. The exact cause is unknown, but it occurs more often in relatives of people with bipolar disorder.

Types of bipolar disorder:

• People with bipolar disorder type I have had at least one manic episode and periods of major depression. In the past, bipolar disorder type I was called manic depression.
• People with bipolar disorder type II have never had full mania. Instead they experience periods of high energy levels and impulsiveness that are not as extreme as mania (called hypomania). These periods alternate with episodes of depression.
• A mild form of bipolar disorder called cyclothymia involves less severe mood swings. People with this form alternate between hypomania and mild depression. People with bipolar disorder type II or cyclothymia may be wrongly diagnosed as having depression.

In most people with bipolar disorder, there is no clear cause for the manic or depressive episodes. The following may trigger a manic episode in people with bipolar disorder:

• Life changes such as childbirth
• Medications such as antidepressants or steroids
• Periods of sleeplessness
• Recreational drug use