The dual factor structure of self-rated MDQ hypomania: energized-activity versus irritable-thought racing

Background: Bipolar II is diagnosed in a clinically depressed patient by documenting history of hypomania. Therefore, it is of great significance for both clinical and research purposes to characterize the factor structure of hypomania. Methods: Among consecutive depressive outpatients—126 major depressives and 187 bipolar II—diagnosed by the Structured Clinical Interview for DSM-IV (Clinician Version), 181 who had clinically recovered from depression were administered the Mood Disorder Questionnaire (MDQ of Hirschfeld et al., 2000. Am. J. Psychiatry 157, 1873). The MDQ is a newly developed, psychometrically validated self-report screening instrument for bipolar spectrum disorders. It screens for lifetime history of manic/hypomanic symptoms by including yes/no items covering all DSM-IV symptoms of mania/hypomania. The MDQ symptom interrelationships were studied by principal component analysis with varimax rotation. Results: Hypomanic symptoms occurring in >50% were racing thoughts, increased energy and social activity, and irritability. Factor analysis revealed two factors: ‘Energized-Activity’ (eigenvalue=3.1) and ‘Irritability-Racing Thoughts’ (eigenvalue=1.5). Limitations: Cross-sectional assessment. Conclusions: Self-assessment of past hypomanic symptoms by patients, during clinical remission from depression, revealed two independent hypomanic factors, neither of which comprised euphoria. Hypomanic behavior appears to be more fundamental for the diagnosis of hypomania than elated mood accorded priority in DSM-IV; of hypomanic moods, irritability had greater significance than elation. It would appear that self-report of euphoria is less likely when hypomanias are brief (⩾2 vs. ⩾4 days). The main implication for busy clinical practice is that energized activity and irritable mood associated with racing thoughts represent the modal experiences of hypomania among bipolar II outpatients; euphoria is neither sensitive, nor pathognomonic, in the diagnosis of these patients. These conclusions accord with recommendations made many years ago for the diagnosis of hypomania among cyclothymic patients [Akiskal et al., 1977. Am. J. Psychiatry 134, 1227].