Bipolar disorder is a physical illness that affects the brain. A bipolar diagnosis requires at least one episode of mania (wired thinking and behaviors that negatively affect one’s ability to function) or hypomania (a less severe form of mania), and the disorder typically includes episodes of depression that alternate with the mania or hypomania. Your specific diagnosis depends on your symptoms.

In the U.S., doctors refer to the Diagnostic and Statistical Manual of Mental Disorders (DSM), which provides several different categories for bipolar disorder:

  • Bipolar I: The classic form of bipolar disorder involves clear-cut manic episodes, usually alternating with periods of major depression and euthymic (even-mood) periods. A single manic episode, even without depression, is sufficient for a bipolar I diagnosis.

  • Bipolar II: People with bipolar II experience depressive episodes that alternate with hypomanic episodes. If mania enters the picture, the diagnosis changes to bipolar I.

  • Cyclothymic disorder: Multiple depressive and hypomanic episodes over the course of at least two years that are severe enough to disrupt life but not extreme enough, in intensity or duration, to warrant a diagnosis of bipolar I or II characterize this form of bipolar.

  • Substance-induced bipolar disorder or bipolar disorder due to a general medical condition: Bipolar symptoms related to intoxication or withdrawal from drugs or alcohol or due to physical illness (such as thyroid disorder, dementia, or brain injury) fall into this category.

  • Bipolar not elsewhere classified (NEC) or not otherwise specified (NOS): This form of bipolar involves variations of cycling moods that resemble manic or depressive episodes and interfere with daily routines but don’t fulfill the complete diagnostic requirements for the other classifications of bipolar disorder in this list.

Physicians outside the U.S. refer to the World Health Organization’s (WHO’s) International Statistical Classification of Diseases and Related Health Problems (ICD), which describes bipolar as “bipolar affective disorder” and classifies it by the current episode’s symptoms:

  • Currently hypomanic

  • Currently manic

  • Currently depressed

  • Mixed disorder

  • In remission