The impact of morningness-eveningness on depression through a serial mediation model of resilience and anxiety.

Objective: Resilience has been recently considered one of the possible mechanisms for the association between morningness-eveningness and depression. Meanwhile, anxiety is closely associated with mood disorder, but its association with morningness-eveningness is unclear. Therefore, this study aimed to explore the mediating effects of resilience and anxiety on morningness-eveningness and depression as the possible mechanisms.

Methods: This study included patient group and nonpatient group. Patient group consists of 743 patients with mood disorders [Major Depressive Disorder (MDD), 233; Bipolar Disorder I (BDI), 113; Bipolar Disorder II (BDII), 397] whereas nonpatient group consists of 818 individuals without mood disorder. The Composite Scale of Morningness, Connor-Davidson Resilience Scale, Self-Rating Depression Scale, and Beck Anxiety Inventory were used to evaluate morningness-eveningness, resilience, anxiety, and depression, respectively.

Results: Our model provided a good fit for the data. The association between morningness-eveningness and depression symptoms was partially serially mediated by resilience and anxiety in both the patient and nonpatient groups. The patient group exhibited significantly stronger morningness-eveningness toward resilience and anxiety than the nonpatient group. In the indirect effect of morningness-eveningness on depression, group differences exist only through each mediation of resilience and anxiety, not through serial mediation.

Conclusion: Our results expand on the mechanism underlying the association between morningness-eveningness and depression. They highlight the importance of morningness-eveningness modification to increase resilience and the need to consider anxiety jointly in this process.