When it was discovered more than 100 years ago, Bipolar Disorder was believed to be the result of "bad blood," thought to be caused by black bile. Later the mental disorder best known for episodes of depression and mania was treated with lithium.

Treatments for Bipolar Disorder have come a long way in the last decade with the development of a new class of anti-psychotics. And yet lithium, one of the oldest treatments still is considered one of the top choices, only lower doses have made it more palatable.

Those suffering from Bipolar Disorder also find that treatments are more effective and customized to the individual patient as compared to a one medication fits all sort of dosing that has been pushed aside as doctors realize that the same doses and treatments have varying degrees of success depending on the patient.

"We've got a new generation of medication with fewer side affects," noted Dr. Melvin G. McInnis, M.D., the Thomas B. and Nancy Upjohn Woodworth Professor of Bipolar Disorder and Depression at the University of Michigan and leader of the school's clinical treatment and research group for Bipolar Disorder. "But the long term challenges remain pretty high."

What is Bipolar Disorder?

Bipolar Disorder is a brain disorder that causes unusual mood shifts from periods of mania where a person feels overly happy and jumpy or wired to severe bouts of depression.

During periods of mania, a person jump from one idea to the next, becomes restless, has trouble concentrating, sleeps little, has unrealistic beliefs about their abilities and acts impulsively, such as going on spending sprees, according to the National Institute of Mental Health.

Conversely, when the low periods occur, the person may feel worried and lose interest in activities, become irritable and in some cases contemplate or attempt suicide.

Some patients also may suffer from hallucinations and delusions during extreme periods of mania or depression. Behavioral problems also are at times linked to the disorder such as alcohol or drug abuse, and many have difficulties with jobs and relationships.

Symptoms can be severe and are not the same as the normal ups and downs that most people experience. At least half of all cases have an onset by the age of 25, though the symptoms may be difficult to recognize and many are not diagnosed right away. About 3 percent of the population is believed to suffer from the mental illness during some point in their life.

The National Institute of Mental Health notes that there are several types of Bipolar Disorder including type I, defined as a disorder with at least one manic episode and periods of major depression, type II, defined as periods of high energy and impulsiveness with no full blown episodes of mania alternating with periods of depression, and cyclothymia, a mild form of Bipolar Disorder with less severe mood swings.

Risk for Bipolar Disorder

The exact cause of Bipolar Disorder remains unknown, though a number or risk factors for the illness have been identified. No one particular risk factor, however, is believed to be sufficient to cause the illness.

Numerous studies have shown a genetic link for Bipolar Disorder, and the genes prompting the illness have been pinpointed. A person can be four to six times more likely to develop the disease if one of their parents or a sibling suffers from the illness.

Advances in technology in recent years have lead to additional studies on how genetics plays a role in developing the illness. The National Institute of Mental Health has helped to launch the Bipolar Disorder Phenome Database, allowing scientists to link visible signs of the disorder with the genes that may influence them.

So far, researchers using this database found that most people with bipolar disorder had missed work because of their illness and suffered from other illnesses at the same time, especially alcohol or substance abuse and panic disorders and been treated or hospitalized for bipolar disorder.

The traits researchers identified that appear genetic include a history of psychiatric hospitalization, obsessive-compulsive disorder in addition to the illness, the age for the first manic episode and the number and frequency of manic episodes.

The continued study of these traits could one day help discover the genes that cause Bipolar Disorder. There are believed to be other risk factors besides genetics such as a person's environment, periods of high stress, drug or alcohol abuse and major life changes such as the death of a loved one, yet these factors alone are not enough to ensure a person will develop the disease.