[Frequency and clinical aspects of bipolar II disorder in a French multicenter study: EPIDEP]

This paper presents the definite data from a French multi-center study (EPIDEP). The aim of EPIDEP was to show the feasibility of validating the spectrum of soft bipolar disorders by practicing clinicians. In this report we focus on data concerning the frequency of BP-II disorder and the key characteristics of BP-II by systematic comparison versus Unipolar depression. EPIDEP involved training 48 french psychiatrists in 15 sites; it is based on a common protocol following the DSM IV criteria (Semi-Structured Interview for Hypomania and Major Depression), and Akiskal (Soft Bipolarity), as well as criteria modified from the work of Angst (Hypomania Checklist), the Ahearn-Carroll Bipolarity Scale, HAM-D and Rosenthal Atypical Depression Scale; Semi-Structured Interview for Affective Temperaments (based on Akiskal-Mallya), self-rated Cyclothymia Scale (Akiskal). Comorbidity and family history (Research Diagnostic Criteria) were also obtained; EPIDEP was globally scheduled in two phases: Phase 1 devoted to recruiting major depressives, and phase 2 involved in more sophisticated assessment of soft bipolarity and administrating related measures. Results are presented on the total of 537 patients included at "visit 1" and 493 assessed for soft bipolarity at "visit 2". The BP-II global rate which was 21.7% at initial evaluation, nearly doubled (39.8%) by systematic evaluation of hypomania. Intergroup comparison versus unipolar depressives showed the following key characteristics of BP-II disorder: 1) distinct clinical presentation at index depressive episode despite uniformity in global intensity of depression (overrepresentation in BP-II of "suicidal thoughts", "guilt feelings", "depersonalisation-derealisation", "hypersomnia" "and weight gain"; and of "psychic anxiety" and "initial insomnia" in UP); 2) different course of illness with younger age of onset of first depression, higher rate of suicidal attempts, recurrency and hospitalisations; 3) more difficulties for recognition of the correct diagnosis; 4) more complex temperamental dysregulations (mixture of cyclothymic, hyperthymic and irritable traits which are highly represented in BP-II group); 5) higher rate in family history of mental disorders, especially bipolar disorders. Finally, EPIDEP data confirmed the diagnostic reliability of self-rating of hypomania and cyclothymia. With a systematic search of hypomania, almost 40% of major depressive episodes seen in psychiatric settings were classified as BP-II, of which only half were recognized by the clinicians at study inclusion. The BP-II validity as a distinct disorder from Unipolars was confirmed. Moreover, EPIDEP emphasized the reliability of self-rating in assessing soft-bipolarity (hypomania and cyclothymia). In total, EPIDEP data indicated that recognition of BP-II is feasible in diverse practice settings and proposed for clinicians some adapted clinical tools for assessing soft bipolarity.