The effects of sleep patterns and chronotype on depressive symptoms in adolescents: a cross-sectional study using data from the 19th Korea Youth Risk Behavior Web-based Survey

Purpose: This secondary data analysis examined the relationship between sleep patterns (including bedtime and wake-up time), chronotype, and depressive symptoms in adolescents aged 13~18 years. Methods: Data were derived from the 19th Youth Risk Behavior Survey conducted in 2023. Of the 52,880 respondents, 5,893 were excluded, resulting in a final analytic sample of 46,987 adolescents. Complex sample logistic regression analyses were conducted using SAS version 9.4 to investigate the effects of sleep patterns and chronotype on depressive symptoms. Results: Among the 46,987 partici-pants, 11,967 reported depressive symptoms, yielding an estimated prevalence of 25.3%. Statistically significant differences in bedtime, wake-up time, sleep duration, and chronotype were identified be-tween adolescents with and without depressive symptoms (p < .001). The mid-sleep time on free days corrected for sleep debt on school days was significantly later among those with depressive symptoms (5.49 ± 0.03) compared with those without (5.36 ± 0.02; p < .001). Significant correlates of depressive symptoms included sex, living with family, household income, school grade, current drinking and smoking, habitual drug use, perceived health status, anxiety, stress awareness, loneliness, and sleep duration. Each additional hour of sleep was associated with a 0.98-fold lower risk of depressive symp-toms (95% confidence interval = 0.96~0.99, p = .021). Conclusion: This study demonstrated that sleep duration, sleep patterns, and chronotype are associated with depressive symptoms in adolescents. In-terventions should target extending sleep duration through earlier bedtimes and encouraging a shift from evening-type to morning-type chronotypes, which may help alleviate depressive symptoms.