0959 Evening Chronotypes Mediate The Association Between Early Life Stress And Emotion Dysregulation In Bipolar Disorder: A Pilot Study

Abstract Introduction In Bipolar Disorder, both circadian rhythms and emotion dysregulation play an important role by negatively influencing its trajectory. In addition many studies documented an association of negative life events and Bipolar Disorder onset and course. The aim was to assess the association between early life stress, chronotypes and emotion regulation in this mood disorder. Methods Fifty two patients (39 females, 47.6 ± 13.1 years) with a Bipolar Disorder- I depressive episode with mixed features, according to DSM-5 and 20 healthy controls (15 females, 47.7 ± 12 years) were recruited. Subjects were evaluated with the SCID-DSM-5 and Morningness Eveningness Questionnaire (MEQ), Difficulties in Emotion Regulation Scale (DERS), Beck Depression Inventory (BDI-II), Mania Rating Scale (MRS) and Early Trauma Inventory-Short Form (ETISR-SF). An a priori power analysis, regression and mediation analyses have been performed. Results In bipolars the MEQ score was 49.2 ± 7.1, with 16 subjects (31%) showing evening chronotypes, and in healthy controls was 58.2 ± 1.5, with 3 (15%) showing evening types (p