Why Are There so Many Classifications of Bipolar Disorder?

Depressed woman with head in hands
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When evaluating symptoms and giving names to bipolar disorder and bipolar disorder's many subsets, there are no absolutes. Researchers and clinicians find that for each new fact learned about bipolar disorder, more questions are raised. Symptoms are different from one person to the next. The severity of symptoms also differs.

Thus, researchers, clinicians, and practitioners face a wide array of challenges in order to "codify" each diagnosis. In response, classification systems, subsets, and specifiers have been developed in an attempt to standardize the diagnostic process.

In the United States, the primary diagnostic system is the one found in the Diagnostic and Statistical Manual of Mental Disorders, also known as the DSM.

Bipolar Disorder in the DSM-5

In a previous version of the DSM (the DSM-IV), bipolar disorder was categorized in the section that included depressive disorders, substance-induced mood disorders, and mood disorders due to a general medical condition. The more recent version of the DSM, the DSM-5, now places bipolar and related disorders in their own disorder class. This category includes bipolar I, bipolar II, and cyclothymic disorder.

A number of additional specifiers also exist:

Specifiers are diagnostic extensions that help clarify the course, features, or severity of the condition.

The DSM-IV also included bipolar disorder not otherwise specified (NOS). This diagnosis was meant to apply to those whose symptoms were representative of bipolar disorder, but that didn't fully meet the criteria for a bipolar disorder diagnosis. In the DSM-5, bipolar disorder NOS was changed to "unspecified bipolar and related disorder" and "specified bipolar and related disorder."

The DSM-5 and DSM-5-TR (fifth edition, text revision) also contain the following groupings:

  • Substance/medication-induced bipolar and related disorder: This diagnosis refers to mania, hypomania, or a major depressive episode that is the result of a substance or medication that a person has taken.
  • Bipolar and related disorder due to another medical condition: This diagnosis is for people who are exhibiting bipolar symptoms (such as mania), but their symptoms are caused by another health condition.

ICD-10 Listing: Mood Disorders

The international diagnostic system is the ICD, or the International Statistical Classification of Diseases and Related Health Problems. The tenth edition, the ICD-10, provides a structure of "families" or related disorders and breaks them down initially into many more categories than the DSM-IV does. Bipolar disorder is within the family of mood (affective) disorders.

  • Manic Episode
  • Hypomania
  • Mania without psychotic symptoms
  • Mania with psychotic symptoms
  • Other manic episodes
  • Manic episode, unspecified
  • Bipolar Affective Disorder
  • Current episode hypomanic
  • Current episode manic without psychotic symptoms
  • Current episode manic with psychotic symptoms
  • Current episode mild or moderate depression
  • Current episode severe depression without psychotic symptoms
  • Current episode severe depression with psychotic symptoms
  • Current episode mixed
  • Currently in remission
  • Other bipolar affective disorders
  • Bipolar affective disorder, unspecified
  • Depressive Episode
  • Mild depressive episode
  • Moderate depressive episode
  • Severe depressive episode without psychotic symptoms
  • Severe depressive episode with psychotic symptoms
  • Other depressive episodes
  • Depressive episode, unspecified
  • Recurrent Depressive Disorder
  • Current episode mild
  • Current episode moderate
  • Current episode severe without psychotic symptoms
  • Current episode severe with psychotic symptoms
  • Currently in remission
  • Other recurrent depressive disorders
  • Unspecified
  • Persistent Mood [Affective] Disorders
  • Cyclothymia
  • Dysthymia
  • Other persistent mood [affective] disorders
  • Unspecified
  • Other Mood [Affective] Disorders
  • Unspecified Mood [Affective] Disorder

Other Classifications

In addition to the two formally recognized diagnostic classifications outlined above, there are quite a few other descriptive systems to be found in the literature. Many of these have been developed by researchers for specific projects or presented as possible alternatives as more is learned about these disorders. One such classification system is that of Young and Klerman who distinguish between six subtypes of manic depression.

Young and Klerman Subtypes

  • Bipolar I - Mania and Major Depression
  • Bipolar II - Hypomania and Major Depression
  • Bipolar III - Cyclothymia
  • Bipolar IV - Antidepressant-Induced Hypo/mania
  • Bipolar V - Major Depression with a family history of Bipolar Disorder
  • Bipolar VI - Unipolar Mania
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3 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. American Psychiatric Association (APA). Diagnostic and Statistical Manual of Mental Disorders. 5th ed, text revision. Washington, D.C.; 2022.

  2. SAMHSA. An introduction to bipolar disorder and co-occurring substance use disorders.

  3. National Institute of Mental Health. Bipolar disorder.