The Relationship Among Seasonality, Night Eating, and Chronotype in Bipolar Disorder: Exploring the Mediating Role of Sleep Quality.

The purpose of the study was to explore the association among chronotype, seasonality, sleep quality, and night eating syndrome (NES) among patients with bipolar disorder (BD) and the mediating role of sleep quality in this relationship. Ninety-two individuals with BD type 1 who had been euthymic for at least 8 weeks and 87 healthy controls were included. In addition to sociodemographic/clinical data, chronotype, seasonality, sleep quality, and NES were evaluated using the Morningness-Eveningness Questionnaire (MEQ), Seasonal Pattern Assessment Questionnaire, Pittsburgh Sleep Quality Index, and Night Eating Questionnaire. The prevalence of NES (17.4%) was higher among BD than the controls. BD patients with NES had poorer sleep quality, greater seasonality, and lower MEQ scores. Chronotype had an indirect effect that was partially mediated by sleep quality on night eating symptoms in BD patients, in addition to a direct effect. Seasonality was found to have a direct effect on night eating symptoms. Therapeutic interventions that target both sleep and circadian disruption should be implemented when addressing NES in patients with BD.