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What is Bipolar Disorder?

A mood disorder marked by episodes of mania or hypomania — elevated or irritable mood with increased energy — usually alongside episodes of depression. It is highly treatable, but often misdiagnosed as depression for years.

From the PsychologyOrbit knowledge base, last updated 2 November 2026.

Knowledge base Updated 2 November 2026 2 views

Bipolar Disorder

A mood disorder marked by episodes of mania or hypomania — elevated or irritable mood with increased energy — usually alongside episodes of depression. It is highly treatable, but often misdiagnosed as depression for years.

Definition

The main forms are:

  • Bipolar I: at least one manic episode, lasting a week or needing hospital care, with elevated or irritable mood, reduced need for sleep, racing thoughts, grandiosity and risky behaviour. Psychosis can occur.
  • Bipolar II: at least one hypomanic episode (milder, shorter, without severe impairment) and at least one major depressive episode.
  • Cyclothymia: long-lasting fluctuations that do not meet full episode criteria.

Depressive episodes are usually the longest and most disabling part of the illness. Lifetime prevalence of bipolar spectrum disorders is around 1 to 2 percent.

History

Descriptions of alternating melancholia and mania go back to antiquity. Kraepelin separated 'manic-depressive insanity' from dementia praecox in the 1890s.

John Cade's report on lithium in 1949 began modern treatment; lithium remains one of the most effective mood stabilisers.

Theory

Bipolar disorder is highly heritable, with genetic overlap with schizophrenia and major depression.

Circadian and sleep disruption is closely tied to episodes: sleep loss can trigger mania, and regular daily rhythms are protective. Stressful life events and some antidepressants used alone can precipitate episodes.

Research

Lithium reduces relapse and has a specific protective effect against suicide. Other mood stabilisers and some antipsychotics are also effective.

Adding psychoeducation, family-focused therapy or interpersonal and social rhythm therapy to medication reduces relapse.

People with bipolar disorder often wait many years for a correct diagnosis, most commonly because they seek help during depression and a previous hypomania goes unrecognised.

Applications

Long-term treatment with mood stabilisers, psychoeducation about early warning signs, regular sleep and routine, relapse prevention plans, and careful use of antidepressants.

Screening for past hypomania is important whenever depression is assessed.

Criticism

  • Bipolar II and the spectrum are debated: broad definitions risk overdiagnosis, narrow ones miss people.
  • Paediatric bipolar diagnoses rose sharply in some countries in the 2000s, raising concern about overdiagnosis in children.
  • Media stereotypes equate the illness with creativity or with unpredictability, both misleading.

References

  • Grande, I., Berk, M., Birmaher, B., & Vieta, E. (2016). Bipolar disorder. The Lancet, 387(10027), 1561-1572.
  • Geddes, J. R., & Miklowitz, D. J. (2013). Treatment of bipolar disorder. The Lancet, 381(9878), 1672-1682.
  • Cipriani, A., Hawton, K., Stockton, S., & Geddes, J. R. (2013). Lithium in the prevention of suicide in mood disorders: Updated systematic review and meta-analysis. BMJ, 346, f3646.
Written for PsychologyOrbit and reviewed before publishing. It is a summary for professionals and students, not clinical guidance, and it is not a substitute for the primary sources listed above.