788 Conditions for Further Study
Diagnostic Features
Individuals with short-durati on hypomania have experienced at least one major depres-
sive episode as well as at least two episodes of 2–3 days’ duration  in which criteria for a hy-
pomanic episode were met (except for symptom duration). These episodes are of sufficient
intensity to be categorized as a hypomanic ep isode but do not meet the 4-day duration re-
quirement. Symptoms are present to a signific ant degree, such that they represent a no-
ticeable change from the individual’s normal behavior.
An individual with a history of a syndromal hypomanic episode and a major depres-
sive episode by definition has bipolar II disord er, regardless of current duration of hypo-
manic symptoms.
Associated Features Supporting Diagnosis
Individuals who have experienced both shor t-duration hypomania and a major depres-
sive episode, with their increased comorbidit y with substance use disorders and a greater
family history of bipolar diso rder, more closely resemble in dividuals with bipolar disor-
der than those with major depressive disorder. 
Differences have also been found between individuals with short-duration hypomania
and those with syndromal bipolar disorder. Work impairment was greater for individuals
with syndromal bipolar disorder, as was the es timated average number of episodes. Indi-
viduals with short-duration hypomania may exhibit less se verity than individuals with
syndromal hypomanic episodes, including less mood lability.
Prevalence
The prevalence of short-duration hypomania is un clear, since the criteria are new as of this
edition of the manual. Using somewhat different  criteria, however, it has been estimated