Rapid-cycling bipolar I disorder: course and treatment outcome of a large sample across Europe.

OBJECTIVES: To evaluate the baseline characteristics and follow-up outcomes of rapid-cycling (RC) bipolar I patients in a large, prospective, observational study.
METHODS: EMBLEM (European Mania in Bipolar Longitudinal Evaluation of Medication) is a long-term prospective observational study of in- and outpatients with an acute mania/mixed episode conducted in 14 European countries. Demographic and clinical variables were collected at baseline, including the presence or absence of DSM-IV rapid-cycling during the past year. Outcome measures included the 5-item Hamilton Depression Rating Scale (HAMD-5) and Young Mania Rating Scale (YMRS) over 12 weeks, as well as the Clinical Global Impressions-Bipolar Disorder Scale (CGI-BP overall, mania and depression) over 12 months.
RESULTS: Of 3684 patients enrolled, 3089 patients provided reliable data to qualify for either RC (N=535, 17.3%) or non-RC (NRC, N=2554), according to DSM-IV. RC prevalence varied across countries (p<0.001). Baseline and 12 week outcomes on the YMRS and HAMD-5, 12 month ratings on the CGI-BP subscales and work impairment at 12 months were significantly different (p<0.001) between groups, being worse in RC. RC patients were more likely to receive antidepressants and lamotrigine (p<0.001). Using logistic regression, RC was associated to country (p<0.001), female sex (p=0.029), outpatients (p=0.035), more history of attempted suicide (p<0.001) and alcohol abuse (p<0.001).
CONCLUSIONS: The EMBLEM results suggest that in naturalistic settings, patients with mania and RC differ from NRC in socio-demographic characteristics, treatment prescriptions and clinical outcome measures with a consistently worse occupational outcome and comorbidities. RC represents a longitudinally severe form of bipolar disorder, with poorly evidence-based diagnostic and therapeutic tools.