Are bipolar disorders underdiagnosed in patients with depressive episodes? Results of the multicenter BRIDGE screening study in Germany

BackgroundRecent reports indicate that the prevalence of bipolar disorder (BD) in patients with an acute major depressive episode might be higher than previously thought. We aimed to study systematically all patients who sought therapy for major depressive episode (MDE) within the BRIDGE study in Germany, reporting on an increased number (increased from 2 in the international BRIDGE report to 5) of different diagnostic algorithms.MethodsA total of 252 patients with acute MDE (DSM-IV confirmed) were examined for the existence of BD (a) according to DSM-IV criteria, (b) according to modified DSM-IV criteria (without the exclusion criterion of ‘mania not induced by substances/antidepressants’), (c) according to a Bipolarity Specifier Algorithm which expands the DSM-IV criteria, (d) according to HCL-32R (Hypomania-Checklist-32R), and (e) according to a criteria-free physician's diagnosis.ResultsThe five different diagnostic approaches yielded immensely variable prevalences for BD: (a) 11.6; (b) 24.8%; (c) 40.6%; (d) 58.7; e) 18.4% with only partial overlap between diagnoses according to the physician's diagnosis or HCL-32R with diagnoses according to the three DSM-based algorithms.ConclusionsThe diagnosis of BD in patients with MDE depends strongly on the method and criteria employed. The considerable difference between criteria-free physician's diagnosis and the remaining algorithms indicate the usefulness of criteria lists within the everyday clinical setting.LimitationsDiagnoses based on DSM were only made with checklists. The diagnoses of (hypo-) manic episodes in the patient history were not systematically verifiable by indirect anamnesis.