BACKGROUND: Individuals with an evening chronotype tend to experience higher rates of comorbid anxiety and depression compared to morning or neutral chronotypes. This study examined the prevalence and compared the network structures of depression and anxiety among Chinese adults across different chronotypes.
METHODS: A national cross-sectional study was conducted from June to August 2023. Depression and anxiety were assessed using the Patient Health Questionnaire (PHQ) and the Generalized Anxiety Disorder Scale (GAD). Network analysis identified central and bridge symptoms using "Expected Influence" and "Bridge Expected Influence" metrics. Network Comparison Tests explored differences across chronotypes.
RESULTS: Among 30,054 participants, the prevalence of depression and anxiety were significantly higher in the evening chronotype compared to morning and neutral chronotypes. Notably, females with evening chronotype reported significantly higher prevalence of depression and anxiety than males. This gender difference was not observed in other chronotype groups. The network structures of depression and anxiety symptoms differed significantly between the evening and morning groups, as well as between the evening and neutral groups. However, no significant differences in the network structure of depression and anxiety symptoms were found between the morning and neutral groups, and no gender-based differences in the network structure of these symptoms were observed within any chronotype group. In the evening chronotype, GAD 4 ("Trouble relaxing") emerged as the central symptom, while PHQ 2 ("Sad mood") served as a bridge symptom, a pattern observed only in this group. In the morning and neutral groups, GAD 2 ("Uncontrollable worrying") was a central symptom, and GAD 5 ("Restlessness") served as both a central and a bridge symptom. GAD 1 ("Nervousness") and GAD 7 ("Felt afraid") were common bridge symptoms across all groups.
CONCLUSION: Depression and anxiety are more prevalent in the evening chronotype. Targeting "Trouble relaxing" and "Sad mood" in evening chronotypes, and "Uncontrollable worrying" and "Restlessness" in morning and neutral chronotypes, may serve as a future prevention and symptom managment strategies. Addressing "Nervousness" and "Felt afraid" could benefit all chronotypes. The mechanism linking chronotype and mental health should be explored through future longitudinal studies including biological and environmental factors.
