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

123 Recurrent brief depressionPrevalenceThe first observation in this regard is that the association of both groups of mooddisorders with RBD is very common: it occurred in 44% of BP-II and 39% of MDD.In terms of weighted prevalence rates, the association was even higher, with 64% and44% respectively. Thus, about half of all subjects with MDEs also manifested RBD.Given the higher recurrence risk of BP versus MDD (Marneros et al., 1991; Angstand Preisig, 1995, Lavori et al., 1996), it is comprehensible that RBD, as a rapidcyclingdepressive condition, was more often associated with BP-II than with MDD.ComorbidityWe hypothesized that combined cases of mood disorders (defined by an associationwith RBD) were clinically more severe than pure cases. Our epidemiologicaldata clearly confirm that the combined forms of BP-II and MDD differ from thepure groups on many measures: earlier age of onset, higher rates of family historyof depression and anxiety, suicidality, treatment, atypicality, comorbidity withanxiety disorders, certain personality disorders and traits (especially impulsivity),and seasonality (in fall/winter as well as spring).Taken together, these characteristics of combined BP-II and MDD convincinglydemonstrate the clinical relevance of the concept of combined mood disorders andof a diagnosis of RBD.Our failure to find that combined mood disorders had a higher association withsubstance abuse/dependence than the pure forms is intriguing. It does not supportthe hypothesis that RBD is a feature of personality disorders. Our findings are inagreement with those of Staner et al. (1992) that RBD was not an unspecificexpression of axis II disorders. Our data also showed no association betweenRBD and sociopathy and conduct problems in adolescence. All this is compatiblewith Pezawas et al. (2002b), who also failed to find an association betweenpersonality disorders (assessed by Structured Clinical Interview) (SKID II)(Wittchen et al., 1998) and RBD in a study of clinical cases.All these findings are in line with the hypothesis that RBD is not associated withpersonality disorders but is linked with affective abnormalities of the personality,such as depressive personality disorders and high impulsivity/irritability scores.Risk of suicide attemptsThe concept of brief depression originated in observations of its frequency amongsuicide attempters in an emergency clinic and in a psychiatric practice (Gregory,1908, 1915; Paskind, 1929, 1930).