A 38-year-old woman with Bipolar Disorder II presents with a 3-week depressive episode (anhedonia, guilt, sleep disturbance, 40% functional decline). She reports a 5-day period 8 months ago of elevated mood, decreased need for sleep (3 hours/night), increased goal-directed activity, and racing thoughts, but she continued working and had no hospitalization. Which finding best supports the diagnosis of Bipolar Disorder II over a major depressive disorder with hypomanic-like features?