The literature suggests that bipolar spectrum disorders are more prevalent than previously thought but still poorly recognized. In the primary care setting, this poor recognition is largely the result of an insensitive, cross-sectional approach and clinicians' lack of familiarity with the phenomenology of bipolar II. Failure to recognize the role of bipolarity in depressive illness is more often a cause of the poor outcome of this illness in this setting than under dosing with antidepressants. Hypomania is easily missed in clinical evaluations and, as currently defined by DSM-IV, may not represent the most diagnostic marker for all variants of bipolar illness: Mood lability and energetic activity, temperamental traits embodied in the construct of cyclothymia, have emerged as more specific. Given emerging data that as much as one third of depressions in both psychiatric and primary care settings belong to the soft bipolar spectrum, practitioner education on the necessity to consider course, temperament, and family history in the approach to depression may improve the identification of bipolar spectrum disorders and limit unproductive or potentially harmful antidepressants use unprotected with mood stabilizers.