Bipolar disorder, formerly known as manic depression, is a mood disorder that involves changes in mood and energy levels. Manic episodes can produce sleeplessness, hallucinations, delusions, rage and psychosis. Additionally, depressive episodes accompanying bipolar disorder may be more severe and difficult to treat than other forms of depression, according to WebMD.
The "Diagnostic and Statistical Manual of Mental Disorders" delineates among different forms of bipolar disorder, explains Mayo Clinic. Bipolar I disorder involves having at least one manic episode in addition to hypomanic or major depressive episodes. Bipolar II disorder requires one major depressive episode with a duration of at least two weeks and a hypomanic episode of at least four days. Cyclothymic disorders involve two years of recurring hypomania symptoms where symptoms occur at least half the time and severely impact a person’s quality of life.
Bipolar disorder usually manifests between the ages of 15 and 24 and lasts throughout a person's life. The precise cause for bipolar disorder is unknown, but experts suggest both genetic and nongenetic factors may contribute to the disorder. People with bipolar disorder commonly have physical changes in their brains such as an imbalance of neurotransmitters. Researchers have not located the precise genes involved in causing the disorder, but it is known that bipolar disorder occurs more frequently in individuals who have a first-degree relative with the disorder. Nongenetic risk factors for the disorder include drug or alcohol abuse, periods of high stress and traumatic experiences, states Mayo Clinic.