Bipolar disorder is a condition in which people experience abnormally elevated (manic or hypomanic) and, in many cases, abnormally depressed states for periods of time in a way that interferes with functioning. Not everyone’s symptoms are the same, and there is no simple physiological test to confirm the disorder. Bipolar disorder can appear to be unipolar depression. Diagnosing bipolar disorder is often difficult, even for mental health professionals. What distinguishes bipolar disorder from unipolar depression is that the affected person experiences states of mania and depression. Often bipolar is inconsistent among patients because some people feel depressed more often than not and experience little mania whereas others experience predominantly manic symptoms. Additionally, the younger the age of onset—bipolar disorder starts in childhood or early adulthood in most patients—the more likely the first few episodes are to be depression. Because a bipolar diagnosis requires a manic or hypomanic episode, many patients are initially diagnosed and treated as having major depression.
- Bipolar disorder (BD), a mood disorder formerly known as “manic depression” and described by alternating periods of mania and depression (and in some cases rapid cycling, mixed states, and psychotic symptoms). Subtypes include:
- Bipolar I is distinguished by the presence or history of one or more manic episodes or mixed episodes with or without major depressive episodes. A depressive episode is not required for the diagnosis of Bipolar I disorder, but depressive episodes are often part of the course of the illness.
- Bipolar II consisting of recurrent intermittent hypomanic and depressive episodes.
- Cyclothymia is a form of bipolar disorder, consisting of recurrent hypomanic and dysthymic episodes, but no full manic episodes or full major depressive episodes.
- Bipolar Disorder Not Otherwise Specified (BD-NOS), sometimes called “sub-threshold” bipolar, indicates that the patient suffers from some symptoms in the bipolar spectrum (e.g. manic and depressive symptoms) but does not fully qualify for any of the three formal bipolar DSM-IV diagnoses mentioned above.
- It is estimated that roughly one percent of the adult population suffers from bipolar I, roughly one percent of the adult population suffers from bipolar II or cyclothymia, and somewhere between two and five percent suffer from “sub-threshold” forms of bipolar disorder.