Types of Bipolar Disorder

Bipolar disorder types are defined by the pattern and severity of symptoms. Learn about the four types of bipolar disorder.

Bipolar disorder, once known as manic depression, was initially thought of as one disorder. Now, however, we know there are several bipolar disorder types. The types of bipolar disorder are differentiated by the presence and severity of specific symptoms, but all include cycling between high mood states (like mania or manic symptoms) and low mood states (depression).

The following are the mood states found in bipolar disorder:

  • Manic Episode (Mania) – a distinct period during which there is an abnormally and constantly elevated, expansive or irritable mood, typically endangering the welfare of the patient or others, lasting at least one week. Mania often requires hospitalization. ) Learn more about Bipolar Mania and the Impact of Manic Symptoms.)
  • Hypomanic Episode (Hypomania) – a milder form of mania that lasts at least four days.
  • Major Depressive Episode (Depression) – a period during which there is either depressed mood (extreme sadness) or the loss of interest or pleasure in nearly all activities, lasting for at least two weeks. (Learn more about Bipolar Depression.)
  • Mixed Episode – a period during which a person experiences both manic and depressive symptoms nearly every day for at least one week. This type of bipolar disorder episode can be the hardest to treat.

Bipolar Disorder Types

Four types of bipolar disorder are listed in the current version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR); even though bipolar disorder is thought to exist along a continuum rather than in discrete categories. For the purposes of diagnosis, the types of bipolar disorder are defined by the patterns and severity of symptoms.1

  1. Bipolar I disorder (also noted as bipolar 1) is characterized by one or more manic or mixed episodes and one or more major depressive episodes. Bipolar I disorder is the most severe form of the illness and is marked by extreme manic episodes.
    (More on What is Bipolar 1 Disorder? Bipolar I Symptoms)
  2. Bipolar II disorder (also noted as bipolar 2) is characterized by one or more depressive episodes accompanied by at least one hypomanic episode. Hypomanic episodes have symptoms similar to manic episodes but are less severe. They still must be clearly different from a person's non-depressed mood. For some, hypomanic episodes are not severe enough to cause notable problems in social activities or work. However, for others, they can be troublesome.
    (More on What is Bipolar 2 Disorder? Bipolar II Symptoms)
  3. Cyclothymic disorder (cyclothymia) is characterized by chronic fluctuating moods involving periods of hypomania and depression; however, the depression does not rise to the level of a major depressive episode. Many with cyclothymia are fully-functioning and possibly hyper-productive if frequent hypomanias occur. Some with cyclothymic disorder eventually develop a more severe type of bipolar disorder.
  4. Bipolar Disorder Not Otherwise Specified (bipolar NOS) is diagnosed when the bipolar disorder is not characterized exactly by any of the above types of bipolar disorder. The depressive and manic/hypomanic experiences of bipolar disorder vary from person to person and the bipolar NOS diagnosis is used as a catchall for bipolar symptoms which do not fall specifically into another bipolar disorder type.

Subtypes of Bipolar Disorder

Most people with bipolar disorder cycle a few times (even less than once) per year and those that cycle four or more times per year are known as rapid-cyclers. It is thought that 15% of people with bipolar disorder rapid cycle. Cycles lasting days (ultra-rapid cycling) or even hours (ultradian cycling) are also possible. These subtypes can be applied to any of the four bipolar disorder types listed above.
(More on Rapid Cycling Bipolar Disorder: Symptoms, Treatment, Effects)

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Last Updated: July 11, 2017

Reviewed by Harry Croft, MD