Here's how to determine if you have bipolar disorder or are at risk of developing it. Includes signs of mania and severe depression.

A Guide for the Newly Diagnosed

The U.S. National Institute of Mental Health estimates that about one in every 100 U.S. adults suffers from bipolar disorder.

The cause of bipolar disorder isn't known. There's a genetic component. Children whose parents have bipolar disorder are at increased risk. If one of a pair of genetically identical twins has bipolar disorder, the other twin doesn't always have it -- although he or she is at higher risk than non-twin siblings are. While genetic makeup plays a role, a combination of factors is most likely to blame.

It's hard to diagnose bipolar disorder. It's often mistaken for clinical depression when depressive mood is the first sign of trouble. And instead of full-blown manic periods, some people with bipolar disorder have only mild or moderate mania -- called hypomania. These people may feel great and be highly productive. It's hard to convince them something is wrong -- until their hypomania ramps up into full-blown mania or they become deeply depressed.

Jane Pauley, the popular television personality, did not know she had bipolar disorder until steroid treatment for severe hives sent her into a series of mood swings.

The key sign of bipolar disorder is the mood swing. This is a continuum of mood states with severe mania at one end and severe depression at the other.

According to the NIMH, signs of a manic episode -- severe mania -- include:

• A feeling that one has abundant energy leading to restlessness and high activity levels
• The experience of feeling ecstatically happy
• Being very irritable
• Racing thoughts and fast speech jumping from one subject to another
• Inability to concentrate
• Very little need for sleep
• Believing that one has unrealistic powers or abilities
• Making bad decisions based on poor judgment
• Spending sprees
• Increased sex drive
• Drug abuse, especially cocaine, alcohol, and sleeping pills
• Provocative or aggressive behavior
• Being sure nothing is wrong

A manic episode is when elevated mood and at least three of these symptoms occur most of the day, every day, for a week or more. If a person has an irritable mood, four other symptoms must be present for it to be officially diagnosed as a manic episode.

Not everyone with bipolar disorder experiences manic episodes. Some people have hypomania -- periods of increased drive, decreased sleep, and feeling "higher" than one's typical self. The symptoms are easy to miss.

"When a person becomes floridly manic, when a person takes off their clothes and runs down the street and starts giving money away, everybody knows something is wrong," says Raison. "But a lot of time they have depression and then people say, 'Oh, look at Mary, she was so depressed and now she's holding down three jobs and doing so well.' Sometimes the signs of hypomania get missed."

According to the NIMH, signs of a depressive episode -- severe depression -- include:

• A long-lasting sad, anxious, or empty mood
• Feeling hopeless or pessimistic
• Feeling guilty, worthless, or helpless
• Losing interest in things one once enjoyed, including sex
• Feeling fatigue or loss of energy
• Difficulty concentrating, remembering, or making decisions
• Feeling restless or irritable
• Sleeping too much, or not being able to go to sleep
• Change in appetite or unintended weight loss or weight gain
• Chronic pain or other body symptoms not caused by physical illness or injury
• Thoughts of death or suicide

A depressive episode is when five or more of these symptoms occur most of the day, nearly every day, for two or more weeks.

Extreme manic or depressive episodes may sometimes include psychotic symptoms such as hallucinations or delusions. These can lead to an incorrect diagnosis of schizophrenia.