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

124 J. Angst et al.The findings of our analysis of suicide attempts are puzzling. They confirm anassociation of RBD with a history of suicide attempts, but its effect as a risk factoralone is smaller than that of MDE or dysthymia. The true clinical significance of RBDis given by its association with MDE. We found the highest suicide attempt ratesamong combined BP-II subjects (38.5%), compared to 25.6% in combined MDD andto 22.6% in pure MDD; this finding is also linked to the greater psychiatric comorbidityof combined cases. On the other hand, our earlier finding that suicideattempt rates in combined MDD were several-fold higher (30%) than in the pureforms (7.7%) (Angst et al., 1990, Merikangaset al., 1990) wasnotconfirmedbythenew data (where the figures were 25.6% versus 22.6% respectively). This may be inpart a consequence of the diagnostic shift of many cases from MDD to BP-II disorder.Searching for further correlates of the association of RBD with suicideattempts, we also analyzed personality traits measured by the FPI. Although,compared to controls, aggressiveness was higher in all diagnostic subgroups ofmood disorders, the latter did not differ from each other. The findings onimpulsivity/irritability were important. Here all diagnostic groups differedfrom controls but, in addition, all groups with RBD scored systematically higherthan the pure-mood-disorder groups. Thus we were unable to replicate thefindings of Pezawas et al. (2002b), who found differences between combineddepression and RBD in clinical cases.We could not examine a postulated impulsivity/aggression factor underlyingsuicidal behavior, which was extracted by factor analysis from theBrown–Goodwin aggression inventory, Buss–Durkee hostility inventory, andBarratt impulsivity scale (Mann et al., 1999) This factor was found in psychiatricinpatients suffering from a cluster of disorders, e.g., alcohol or drug dependence,borderline personality disorder, cigarette smoking and aggressive, impulsive behaviors.These disorders and behaviors were significantly associated with suicideattempts. Furthermore, aggressiveness/impulsivity was recently shown to belinked to a malfunctioning serotonergic system (Mann et al., 2001; Pezawaset al., 2002b). Since our analysis was based only on multiple variables, thisrelationship may have been missed on account of power problems. However,biserial correlations and logistic regressions failed to confirm those findings inour study. On the other hand we were able to show that the risk for suicideattempts was linked to gender and to a diagnosis of MDE plus RBD.What is the nature of RBD?We do not think that RBD is only a residual syndrome of MDEs, fluctuating inshort recurrences, as first described in Sardinia (Carta et al., 1994) or the residualsof dysthymia (Angst and Wicki, 1990). RBD can undoubtedly also precede MDD.