 The concerns with the use of antidepressants in known bipolar depression have focused on antidepressant - induction of mania, and rapid cycling but these do not always present themselves immediately. However, there may be other subtle and immediate antidepressant treatment effects that make the diagnostic distinction possible and more pressing.5,10Indeed, it has been postulated that undetected bipolar depression may explain the apparent poor treatment response and increase in suicidality with the use of antidepressants in the adolescent population, where one might expect an increased prevalence of depression as first episode of bipolar disorder by virtue of earlier age of onset compared to unipolar illness.11 