Bipolar II is not a milder bipolar, despite its gentler highs
Bipolar II swaps full mania for hypomania, a lift in mood and energy that can pass for a productive streak. That subtlety is the trap: people usually seek help only when depressed, and many are misdiagnosed with ordinary depression. Yet the condition carries burdens as heavy as bipolar I, with depression dominating its course.
A diagnosis needs at least one hypomanic episode and at least one episode of major depression, and no full manic episode ever; a single bout of mania would reclassify the illness as bipolar I. Hypomanic episodes must last at least four days. During them a person may feel euphoric or irritable, sleep less, talk fast, leap between ideas and take on risky spending or investments. Unlike mania, hypomania never involves psychosis and does not reach the level of needing hospital care.
Because those highs resemble high-functioning behaviour or plain personality, patients often do not notice them, and many have stretches of normal mood in between. Depression, by contrast, is frequent and intense. Estimates of how much it predominates range widely, from a ratio as high as 39 to 1 down to about 4 to 1 in studies using clinician-adjusted daily mood diaries. Compared with bipolar I, the type II course tends to be more chronic, with more cycling and shorter well periods, and it is linked to a greater risk of suicidal thoughts and behaviour.
Telling it apart from major depressive disorder is hard; research on reliable differences is inconsistent. Some clinicians note that people later found to be bipolar often showed oversleeping, increased appetite, slowed movement, or hypomania triggered by antidepressants. An earlier age of onset, more frequent recurrence and a family history of bipolar disorder also point towards it. Episodes with mixed features, in which symptoms of both poles overlap, can last months and resist treatment.
Causes are not fully understood, with genetic, environmental and neurobiological factors all thought to contribute. Management typically combines mood stabilisers or atypical antipsychotics with psychotherapy. Antidepressants are contested: some studies report benefit, while others find a risk of triggering hypomania or faster cycling, and using them without a mood stabiliser has been associated with worsening symptoms.
Source: Bipolar II disorder
