Bipolar Disorders: Mixed States, Rapid-Cycling, and Atypical Forms

372 G. Sachs and M. Graves52%31% 37:1BPIIBPI10%% weeksDepressionBPI 1.4%BPII% weeksManic spectrumFig. 17.2 Course over 15-year follow-up. Bipolar I (BPI), n = 135; bipolar II (BPII), n = 71.Adapted from Judd et al . (2002).Robb et al. (1997) employed a self-report measure, the Illness IntrusivenessRating Scale, and found that euthymic BP-II patients suffered greater impairmentthan BP-I subjects (Robb et al., 1997).Judd et al. (2002) compared the course of illness for BP-I (n ¼ 135) andBP-II (n ¼ 71) followed in the National Institute of Mental Health (NIMH)Collaborative Depression Study over 15 years of follow-up. Figure 17.2 showsoutcomes from the Longitudinal Interval Follow-up Evaluation (LIFE: Keller et al.,1987), one of the few measures that harvests systematic data over time periodssufficiently long enough to describe course of illness. The impressive differences inpercentage of weeks depressed (BP-I ¼ 31%; BP-II ¼ 52%) and the ratio of weeksdepressed to weeks with hypomaniaþmania (BP-I ¼ 3:1; BP-II ¼ 37:1) demonstratesthe possibility for capturing long-term outcomes.Difficulties in conducting clinical trials for mixed episodesThe DSM-IV definition of mixed episodes requires a period of at least 1 weekduring which a patient meets full criteria for mania and major depression. Fewstudies reporting results for mixed episodes, however, use the DSM-IV definition.Leaving aside the confusing array of ‘‘mixed states’’ described as fulfilling one ormore criteria for ‘‘mixiety’’ (Akiskal and Pinto, 1999), many studies of mixed statesare problematic. Within the limits of brevity permissible here, it is possible tohighlight only two commonly underappreciated issues related to interpretation ofstudies reporting results for mixed states.Some studies operationalize the term ‘‘mixed state’’ by using cut-off scores onformal rating scales, which are not validated as diagnostic instruments. For