Psychology › Mental health & disorders › Depression and mood disorders
Bipolar disorder
Kraepelin 1899; renamed 1980· Condition or disorder
Well replicatedStrong, repeated evidence.
A mood disorder in which episodes of mania or hypomania (abnormally high energy and mood) alternate with depression.
See it on the Psychology map →What it says
French psychiatrists described 'circular insanity' in the 1850s; in 1899 Emil Kraepelin separated manic-depressive illness from schizophrenia, and DSM-III renamed it bipolar disorder in 1980. Mania brings little need for sleep, racing thoughts, grand plans and risky spending; bipolar I involves full mania, bipolar II milder hypomania plus depression. About 1 to 2 percent of people are affected, with heritability near 70 percent. Mood stabilizers such as lithium, plus therapy, help most people live full lives.
Why it matters
Correct diagnosis often takes years, because people seek help when depressed. Manic spending can wreck finances, so some families agree on safeguards ahead of time.
The evidence
Family, twin and adoption studies show strong heritability; long-term trials since the 1960s show lithium prevents relapses; genome studies have found dozens of risk genes.
Open questions
What biologically switches a brain between mania and depression is unknown, and where the edges of a broader 'bipolar spectrum' lie is debated.
Connections (2)
▸Bipolar disorder includes episodes of Depression and mood disordersWell replicated
The connection
Most people with bipolar disorder spend far more time depressed than manic. Their depressive episodes look like ordinary depression, so many are first diagnosed with major depression and given antidepressants alone, which can trigger mania. Mood stabilizers are usually needed instead.
Who showed it and when
Kraepelin grouped mania and depression as one illness in 1899; Jules Angst and Carlo Perris separated bipolar from 'unipolar' depression in 1966.
The evidence
Lewis Judd's long-term NIMH follow-up found bipolar I patients had symptoms in nearly half of all weeks, mostly depressive.
Open questions
Whether antidepressants should ever be used in bipolar depression, and how to spot bipolar risk at a first depressive episode, are debated.
▸Lithium for bipolar disorder stabilizes mood in Bipolar disorderWell replicated
The connection
Lithium dampens manic highs and, to a lesser degree, depressive lows, and taken long term it prevents many future episodes. It is particularly good at preventing mania and suicide. About a third of patients respond very well; others respond partly or not at all.
Who showed it and when
John Cade, Melbourne, 1949; Mogens Schou's trials in Denmark from 1954; US FDA approval for mania in 1970.
The evidence
Randomized trials and meta-analyses show lithium reduces relapses and suicides compared with placebo and with several other drugs.
Open questions
How it works is unknown, and why some patients respond dramatically while others do not is being studied genetically.