Bipolar Disorder
Bipolar disorder is a category of mood disorders defined by the presence of one or more episodes of abnormally elevated mood, clinically referred to as mania. Individuals who experience manic episodes also experience depressive episodes or symptoms, or mixed episodes in which features of both mania and depression are present at the same time.

These episodes are normally separated by periods of normal mood, but in some patients, depression and mania may rapidly alternate, known as rapid cycling. Extreme manic episodes can sometimes lead to psychotic symptoms such as delusions and hallucinations. The disorder has been subdivided into bipolar I, bipolar II, Bipolar NOS, and cyclothymia based on the type and severity of mood episodes experienced.

Also known as bipolar affective mood disorder before, and the current name is of recent origin and refers to the cycling between high and low episodes; it has replaced the older term manic-depressive illness coined by Emil Kraepelin (1856–1926) in the late nineteenth century.The new term is designed to avoid the social stigma associated with the conflation of "manic" and "depression."

Treatments
It is believed that bipolar disorder cannot be cured instead, the emphasis of treatment is on effective management of acute episodes and prevention of further episodes by use of pharmacological and psychotherapeutic techniques.

With this disease, people may be hospitalized especially with manic episodes. This can be voluntary or (if mental health legislation allows it) involuntary (called civil or involuntary commitment). Long-term inpatient stays are now less common due to deinstitutionalization, although can still occur. Following a hospital admission, support services available can include drop-in centers, visits from members of a community mental health team or Assertive Community Treatment team, supported employment and patient-led support groups.

Medication
The mainstay of treatment is a mood stabilizer medication; these comprise several unrelated compounds which have been shown to be effective in preventing relapses of manic, or in the one case, depressive episodes. The first known and "gold standard" mood stabilizer is lithium, while almost as widely used is sodium valproate,originally used as an anticonvulsant. Other anticonvulsants used in bipolar disorder include carbamazepine,reportedly more effective in rapid cycling bipolar disorder, and lamotrigine,which is the first anticonvulsant shown to be of benefit in bipolar depression.

Treatment of the agitation in acute manic episodes has often required the use of antipsychotic medications, such as Quetiapine, Olanzapine,and Chlorpromazine. More recently, Olanzapine and Quetiapine have been approved as effective monotherapy for the maintenance of bipolar disorder. A head-to-head randomized control trial in 2005 has also shown olanzapine monotherapy to be as effective and safe as lithium in prophylaxis.

Usage of antidepressants to people with bipolar disorder has been debated. With some studies reporting a worse outcome with their use triggering manic, hypomanic or mixed episodes, especially if no mood stabiliser is used. However, most mood stabilizers are of limited effectiveness in depressive episodes.