Bipolar disorder occurs in many forms, including bipolar I disorder, bipolar II disorder, cyclothymic disorder and rapid-cycling bipolar disorder. These disorders involve episodes of both mania and depression that vary in length and severity, notes WebMD.
In bipolar I disorder, the patient has had one or more manic episodes, which are characterized by abnormally elevated mood and behavior. These manic episodes typically cause impairment in the patient's life and sometimes require hospitalization, according to Mayo Clinic. They are often followed by a period of severe depression.
In Bipolar II disorder, the patient has less severe manic episodes, which doctors call hypomania, followed by major depression, says WebMD. In between episodes, the person often experiences a relatively stable mood.
Cyclothymia involves fluctuating periods of hypomania and mild depression. Adults must have had symptoms for about two years before doctors diagnose cyclothymia; in children the period is one year. Symptom-free periods for children and adults last for about one month and two months respectively, according to Healthline.
In rapid-cycling bipolar disorder, the patient experiences at least four episodes of mania, hypomania, depression or mixed states in one year. A rapid-cycling pattern is often associated with severe depression and suicide attempts. Women are more likely to develop rapid cycling than men, notes WebMD.