vidual ages. While the hypomanic episode is the feature that defines bipolar II disorder,
depressive episodes are more enduring and disabling over time. Despite the predomi-
nance of depression, once a hypomanic epis ode has occurred, the diagnosis becomes bi-
polar II disorder and never reve rts to major depressive disorder.
Approximately 5%–15% of individuals with bipolar II disorder ha ve multiple (four or
more) mood episodes (hypomanic or major depressive) within the previous 12 months. If