Is the DSM-5 duration criterion valid for the definition of hypomania?

DSM-IV and DSM-5 impose a 4 day duration criterion for hypomanic episodes yet several studies have suggested that such an imposition may be invalid. We report a study involving a large sample pursuing the likely salience of the DSM duration criterion.

We analyzed data on hypomanic symptoms provided by two bipolar screening measures - the Mood Disorders Questionnaire (MDQ) and the Mood Swings Questionnaire (MSQ) in a sample of 501 patients meeting DSM and other symptom criteria for a bipolar II disorder (BP II) and contrasted data for 186 meeting the DSM minimum duration of 4 days and 315 experiencing episodes lasting less than 4 days (i.e. 'standard' vs. 'brief' groups).

The brief group reported slightly less severe hypomanic episodes, but the two groups did not differ on a number of illness correlates including age of onset of depressive and of hypomanic episodes, or by rates of depressive and bipolar conditions in first-degree family members.

The possibility of false positive BP II diagnoses, especially with brief hypomanic episodes, must be conceded while our examination of clinical symptoms was limited to two measures.

This study is consistent with previous studies suggesting that the DSM duration of 4 or more days for a diagnosis of a hypomanic episode is unnecessary to the clinical definition of a BP II disorder. Its preservation is likely to exclude a substantive number of those with a true BP II condition.