Weekday Unstructured Time and Depressive Symptoms Among Out-of-School Youth: A Five-Wave Within- and Between Analysis

Background/Objectives: School-based health research may underrepresent out-of-school adolescents. This study examined unstructured time use and subsequent depressive symptoms in a cohort recruited during adolescence. Methods: The analysis used five annual waves (2013–2017) of the Korean Dropout Youth Panel Survey. At Wave 1, the 629 participants were aged 14–19 years (mean 16.81). Outcome assessments at ages 15–23 reflected follow-up of the same cohort. Lagged generalized estimating equations related weekday unstructured time at t − 1 to depressive symptoms at t, adjusting for prior symptoms and covariates (1795 person-waves). Additional analyses separated between- and within-person exposure components, examined the reverse direction, and assessed poor self-rated health. Results: Each additional hour/day of unstructured time corresponded to a 0.013-point higher depressive-symptom score one year later (95% CI, 0.005 to 0.020), approximately 0.07 SD of the outcome per 1-SD exposure difference. The between-person component was positive (b = 0.028; 95% CI, 0.018 to 0.038); the within-person component was not statistically significant (b = −0.008; 95% CI, −0.018 to 0.003). Prior depressive symptoms showed an association with subsequent unstructured time (b = 0.518 h/day per scale point; 95% CI, 0.248 to 0.789). The association with poor self-rated health was not significant. Conclusions: The central finding was a positive between-person association alongside insufficient evidence of a positive within-person association. These findings may inform assessment of daily routines and mood among young people who left school during adolescence and continuing support into adulthood, but do not establish reciprocal causation or benefits from reducing unstructured time.