(A) More than 4 episodes per year # RAPID CYCLING MOOD DISORDER has an earlier age of onset (third decade) than recurrent depressive (unipolar) disorder. Unipolar depression, on the other hand, is common in two age groups: late third decade and fifth to sixth decades.> An average manic episode lasts for 3-4 months and a depressive episode lasts from 4-6 months. Unipolar depression usually lasts longer than bipolar depression.> With rapid institution of treatment, the major symptoms of mania are controlled within weeks and of depression within 6-8 weeks.> Nearly 40% of depressive with episodic course improve in 3 months, 60% in 6 months and 80% improve with in a period of one year. 15-20% of patients develop a chronic course of illness, which may last for two or more years. Chronic depression is usually characterized by less intense depression, hypochondriacal symptoms, presence of comorbid disorders (like dysthymic disorder, alcohol dependence, personality disorders and medical disorders), presence of ongoing stressors and unfavorable early environment.> As the age advances, the intervals between two episodes shorten and, the duration of the episodes and their frequency tends to increase. Although not all patients have relapses, it has been estimated that up to 75% of patients have a second episode within 5 years.> Some patients with bipolar mood disorder have more than 4 episodes per year; they are known as rapid cyclers.> About 70-80% of all rapid cyclers are women.> When phases of mania and depression alternate very rapidly (e.g. in matter of hours or days), the condition is known as ultra-rapid cycling.> Some of the factors associated with rapid cycling include the use of antidepressants (especially tricyclic antidepressants), low thyroxin levels, female gender, bipolar II pattern of illness, and the presence of neurological disease.> There is an increased mortality in patients with mood disorders by almost two times the general population. The most important cause of death is suicide, the life-time risk of which is 10-15 times higher in depression. Patients with depression also have higher mortality rates from cardiovascular diseases and co-morbid alcohol and drug use disorders. Patients with depression also exhibit a variety of disturbances in immune function.