Intergenerational coresidence and parental depression: A discrete-time survival analysis of the ‘boomerang kids’ phenomenon

The return of adult children to the parental home—a phenomenon often referred to as “boomerang kids”—has become more prevalent amid economic instability. While widely observed, limited evidence exists on its impact on parental mental health, particularly in the East Asian context. We used longitudinal data from the Korean Welfare Panel Study (KoWePS), identifying 2479 adult children and their 4659 co-residing parents.. The primary exposure was the return of adult children, defined by changes in co-residence. Discrete-time survival analysis with a complementary log-log link modeled time-varying exposures and covariates. Subgroup analyses were stratified by the employment status of returning adult children. Parents whose adult children returned had a significantly higher depression incidence (40.2 vs. 13.6 per 1000 person-years, HR 2.00), especially when the returning child was unemployed (HR 1.35). Co-residence was not significantly associated with depression among adult children (HR 0.54). The highest risk for adult children was among those unemployed and living apart (HR 1.23). Co-residence following adult children's return was linked to increased depression risk in parents especially when the returning child was unemployed. These findings highlight the need for intergenerational policies that reduce emotional and financial burdens on older adults. • Parental depression risk increased after adult children returned home. • Depression risk was highest when returning children were unemployed. • Adult children's co-residence was not linked to increased depression. • Discrete-time survival analysis captured time-varying co-residence effects. • Findings support intergenerational policy responses to economic strain.