Morningness-eveningness, depressive symptoms, and emotional eating: a population-based study.

The aim of this study was to increase understanding of the associations between different dimensions of morningness-eveningness, depressive symptoms, and emotional eating in the general population. The participants were 25-to-74-year-old Finnish men (n = 2325) and women (n = 2699) from the National FINRISK Study conducted in 2007. The Center for Epidemiological Studies - Depression Scale and the Three-Factor Eating Questionnaire-R18 were used to measure depressive symptoms and emotional eating. Chronotype was assessed with a shortened version of Horne and Östberg's Morningness-Eveningness Questionnaire (MEQ). Structural equation modeling was used as an analytical approach. Confirmatory factor analysis indicated a two-factor structure for the six-item MEQ with separate factors for morning alertness and circadian preference for daily activities (r = 0.65). Higher alertness in the morning and preference for morning hours were both related to lower depressive symptoms (βtotal effect = -0.36 and -0.11, respectively) and emotional eating (βtotal effect = -0.20 and -0.09; βindirect effect through depressive symptoms = -0.12 and -0.04, respectively), even though the relationships with morning alertness were stronger. However, the associations of circadian preference with depressive symptoms and emotional eating were reversed after adjustment for morning alertness. Finally, among participants who rarely or never experienced sleeping sufficiently, those in the lowest (i.e. eveningness) and higher (i.e. morningness) circadian preference/morning alertness quartiles had the highest depressive symptom scores. In conclusion, the findings emphasize the importance of separating between different dimensions of chronotype when examining its relationships with psychological factors such as depressive symptoms and overeating tendencies.