Purpose: This study investigated the interrelationships among postpartum depression, marital conflict, and smart phone overdependence within the Actor-Partner Interdependence Mediation Model (APIMeM) framework. Methods: This study employed a secondary cross-sectional design using dyadic data from the first wave of the 2022 Korean Early Childhood Education and Care Panel Study. The sample included 925 married couples raising their first child in the early postpartum period. The APIMeM was analyzed with AMOS version 23.0, utilizing 10,000 bootstrap resamples to evaluate actor and partner effects and the mediating role of marital conflict. Results: Postpartum depression significantly predicted marital conflict, which partially mediated its impact on smartphone overdepend ence. Only actor effects were statistically significant, indicating that each partner's depressive symptoms affected their own marital conflict and smartphone overdependence. Despite mixed fit indices, the APIMeM was considered interpretable given the constrained structure of dyadic mediation models, accounting for 8.5% of the variance in husbands' smartphone overdependence and 10.5% in wives. Conclusion: Interventions targeting postpartum de pression during the early postpartum period may help reduce smartphone overdependence by enhancing individual emotional regulation, with dyadic coping and relationship quality serving a complementary role to support healthy parenting and infant development.

https://doi.org/10.12934/jkpmhn.2025.34.4.524