Chronotype and biological rhythms in bipolar disorders

• Published in: European psychiatry 2021-04, Vol.64 (S1), p.S622-S622
• Main Authors: Ahmed, A. Ben Cheikh, Ouali, U., Bouslama, I., Zgueb, Y., Nacef, F.
• Format: Article
• Language: English
• Subjects: Abstract; Biological rhythms; Bipolar disorder; Bipolar Disorders; BRIAN scale; chronotype; Circadian rhythm; E-Poster Viewing
• ISSN: 0924-9338; 1778-3585
• DOI: 10.1192/j.eurpsy.2021.1653

IntroductionBiological rhythms play an important role in the etiology of mood disorders. Several lines of evidence established a link between circadian rhythm disruption and mood episodes. Chronotypes are the behavioral manifestations of circadian rhythms and eveningness appears to be more frequent in bipolar disorder (BD). The influence of chronotype on mood symptoms needs yet to be clarified.Objectives-Identifying the predominant chronotype in a Tunisian sample of patients with BD -Assessing the association between chronotype and biological rhythm disruptions in the sampleMethodsFor this study, a total of 80 euthymic outpatients with bipolar disorder and 80 control subjects were recruited. Biological rhythms disruptions were assessed using the Biological Rhythm Interview of Assessment in Neuropsychiatry (BRIAN). Predominant chronotype was identified using the composite scale of morningness (CSM).ResultsBRIAN scores showed greater biological rhythms disruptions in bipolar patients than the control subjects (mean scores 35.26±9.21 vs 25.84±2.68). Low CSM scores in the patients’ group indicated a predominant evening chronotype whereas an intermediate chronotype was more frequent within the control group. The correlation analysis revealed a statistically significant negative correlation between the 2 scales (r=-0.716, p