Refining the evaluation of bipolar II: beyond the strict SCID-CV guidelines for hypomania

Background: The prevalence of bipolar II disorder in depressed outpatients is much higher than previously reported, a finding probably related to systematic probing for past hypomania by trained clinicians. Our objective was to further refine the strict SCID-CV guidelines for hypomania in depressed outpatients. Methods: 168 consecutive outpatients presenting with major depression were systematically interviewed with the SCID-CV about all past hypomanic behavior, irrespective of duration and initial negative response to the screening question on mood. Once typical hypomanic behaviors were elicited, the patient was re-questioned about mood change. Results: The prevalence of bipolar II was 61.3%. Bipolar II, so-defined, was indistinguishable at age of onset, recurrence, and atypical features from a previous sample of 251 BP-II patients interviewed by the same clinician (FB) without the present modification of the stem question on mood, and which had yielded a prevalence of 45% in the same outpatient clinic. Limitations: Single interviewer, and cross-sectional assessment. Conclusions: Systematic probing for all past hypomanic symptoms and behaviors, independently of the answer to the screening question on mood, can elicit hypomanic features that would otherwise be discarded by strict adherence to the SCID-CV. A net gain of 16% in the diagnosis of BP-II can thereby be achieved.