Parental Attachment and Depression Among Adult Non-Disabled Siblings of Individuals with Developmental Disabilities: The Mediating Role of Stress and the Moderating Role of Family Resilience in South Korea

Non-disabled siblings of individuals with developmental disabilities, such as intellectual disability or autism spectrum disorder, frequently encounter increased caregiving stress and affiliate stigma due to their sibling's condition, which can result in significant mental health challenges. According to South Korean government statistics in 2022, these siblings are over seven times more likely to experience anxiety and depression compared to their peers in the general population. Often, these siblings face difficulties in forming secure attachments with their parents, as parental attention is disproportionately directed towards the sibling with a disability. When secure attachment is not established during childhood, this disruption often persists into adulthood, contributing to elevated levels of perceived stress and an increased risk of developing mental health issues such as depression. Family resilience, however, may serve as a protective factor that mitigates the adverse impact of perceived stress on depression. As the family's capacity to adapt positively to adversity, family resilience plays a crucial role in alleviating stress and emotional distress in adult non-disabled siblings. Accordingly, this study aims to examine the mediating role of perceived stress in the relationship between parental attachment and depression among adult non-disabled siblings of individuals with developmental disabilities, as well as the moderating effect of family resilience within this relationship. Based on the findings, the study seeks to offer practical implications for the development of family-based support programs to promote mental health in this population.

Data were drawn from the 2021 Survey on the Socio-Emotional Status of Non-Disabled Siblings in Families with IDD, conducted by the Seoul Disabled Family Support Center and Yonsei University. The sample included 164 non-disabled siblings. Parental attachment was assessed using the Inventory of Parent and Peer Attachment (IPPA); depression, PHQ-9; stress, Perceived Stress Scale (PSS); and family resilience, Family Resilience Assessment Scale (FRAS). Controls included gender, age, education, economic and marital status, parental health and economic status, and sibling gender and disability level. Moderated mediation analysis used SPSS 27.0 and PROCESS Macro v4.3.

The results of the mediation analysis revealed that parental attachment indirectly reduced depression by lowering stress, while its direct effect on depression was not statistically significant. The moderation analysis further showed that family resilience moderated the relationship between stress and depression. Moreover, a moderated mediation effect was observed, confirming that the indirect effect of parental attachment on depression via stress was moderated by the level of family resilience.

The study identified that parental attachment indirectly mitigates depression by reducing perceived stress, with this pathway being moderated by family resilience. Based on these findings, three practical implications are proposed. First, legal frameworks should formally recognize adult non-disabled siblings of individuals with DD as independent recipients of disability-related support. Second, interventions aimed at strengthening parental attachment are necessary, including structured communication training and shared family activities. Third, family-based social work programs that enhance family resilience—particularly those involving both adult non-disabled siblings and individuals with DD—should be institutionalized through family support centers and community mental health agencies, and integrated into local care systems to ensure sustained accessibility.