Antidepressant treatment-associated behavioural expression of hypomania: a case series.

OBJECTIVE: Emerging literature suggests that hypomanic behaviour may be clinically more important than elated mood in spontaneous hypomania. This report describes dysfunctional behavioural activation as a milder expression of antidepressant-associated hypomania.

METHOD: Five outpatients with mood disorders developed problem behaviours following antidepressant treatment. These behaviours include gambling, excessive spending, increased sexual activity, excessive shopping and socially inappropriate verbal aggression. These behaviours were not accompanied with noticeable euphoria or persistent dysphoria and were not characteristics of the individual's personality functioning. They were reported by significant others and patients had no history of primary impulsive, substance abuse or personality disorders.

RESULTS: The observed antidepressant-associated behavioural activation was suggestive of hypomanic behaviours not of impulse control disorders because of; (a) absence of other accountable mental or medical disorders characterized by impulsivity, (b) the evidence of close association between impulsivity and hypomanic/manic states, (c) increasing awareness of the diagnostic importance of behavioural disturbances in hypomania, (d) the substantial evidence relating antidepressant treatment to the emergence of hypomania, but not to impulse control disorders, (e) the well documented therapeutic effect of selective serotonin reuptake inhibitors (SSRIs) in impulse control disorders.

CONCLUSIONS: In accordance with the recent proposed revision in the diagnostic criteria of hypomania, the observed dysfunctional behavioural activation during antidepressant treatment may represent milder expression of antidepressant-associated hypomania. More research is warranted to study the behavioural expression of hypomania secondary to antidepressants.