Balancing the 24-hour lifestyle: A population-based study on reducing mental health problems, self-injurious thoughts and behaviors among adolescents

J Affect Disord. 2025 May 19:119451. doi: 10.1016/j.jad.2025.119451. Online ahead of print.

ABSTRACT

BACKGROUND: Grounded in the 24-Hour Activity Cycle framework, this study aimed to quantify dose-response thresholds for seven daily behaviors-sleep, napping, low to high intensity physical activity, sedentary time, and screen time-and to evaluate their associations with mental health problems and self-injurious thoughts or behaviors in Chinese adolescents.

METHODS: Between 2022 and 2023, data were collected from 33,397 Chinese students to examine lifestyle patterns and mental health. Adjusted logistic regression estimated associations between behavioral categories and four mental-health outcomes, and generalized additive models captured dose-response relationships.

RESULTS: Compared with non-nappers, adolescents who napped 60-90 min daily had 16 % lower odds of suicidal risk (OR 0.84; 95 % CI 0.73-0.97), while moderate-intensity exercise on at least two days per week was associated with 12-31 % reduced odds across all mental health outcomes (OR range 0.69-0.88). Conversely, sleep under 7 h, daily sedentary time over 7 h, and screen time exceeding 4 h were linked to higher risk of adverse outcomes. Generalized Additive Models confirmed significant nonlinear dose-response relationships and identified a common set of healthy lifestyle ranges across all four outcomes: 7.5-10.5 h of sleep, over 40 min of napping, <7.5 h of sedentary time, and under 4.4 h of screen time per day.

CONCLUSIONS: These results provide critical evidence for designing policies and school-based programs aimed at fostering healthier daily routines, ultimately promoting the mental health and resilience of children and adolescents.

PMID:40398616 | DOI:10.1016/j.jad.2025.119451