Euthymia is not always euthymia: Clinical status of bipolar patients after 6 months of clinical remission

Introduction Most studies selected euthymic patients with bipolar disorder in inter-episodic phase according to clinical remission criteria at least between 1 and 6 months. However, possible differences can exist in the course of clinical symptoms in bipolar patients related to the duration of clinical remission. Objectives The main aim of this study was to evaluate the clinical status of bipolar patients after 6 months of clinical remission. Methods We performed a cross-sectional study of bipolar outpatients in clinical remission for at least 6 months. Bipolar Depression Rating Scale (BDRS), Young Mania Rating scale, Pittsburgh Sleep Quality Index (PSQI) scale, Visual Analogic Scales (VAS) evaluated cognitive impairment were used to assess residual symptomatology of patients. Multivariate analysis (MANCOVA) was conducted for analysing possible differences between 3 groups of patients according to their duration of clinical remission (< 6 months–1 year, < 1 year–3 years, < 3 years–5 years). Results A total of 525 patients were included into the study. The multivariate analysis indicated a significant effect of the duration of clinical remission on the different residual symptoms (Pillai's trace: F 4.48, P < 0.001). The duration of clinical remission was associated with the significant improvement of the BDRS total score ( P = 0.013), the PSQI total score ( P < 0.001) and the cognitive VAS total score ( P < 0.001) Conclusion These results support a possible improvement of residual symptoms according to the duration of clinical remission in bipolar patients. Any definition of euthymia should specify the duration criteria. Disclosure of interest The authors have not supplied their declaration of competing interest.