Threshold-Dependent Links Between Attachment Insecurity and Internalizing Symptoms: The Role of Emotion Regulation in Clinical Youth.

Insecure attachment has been consistently linked to internalizing symptoms in children and adolescents, yet the mechanisms underlying this association remain insufficiently understood. Emotion regulation difficulties may play a key moderating role, influencing how attachment-related vulnerabilities are associated with emotional problems. Using a cross-sectional design, this study investigated whether emotion regulation difficulties moderate the association between attachment insecurity (anxiety and avoidance) toward mothers and fathers and internalizing symptoms. Participants were 550 clinically referred children and adolescents (66% girls, aged 8-18), who completed self-report measures assessing attachment insecurity (ECR-RC), emotion regulation difficulties (DERS), and internalizing symptoms (SDQ). Model-Based Recursive Partitioning (MOB) identified emotion regulation thresholds that moderated attachment-symptom associations. Results showed that emotion regulation difficulties moderated these associations in a threshold- and parent-specific manner. Maternal attachment anxiety was associated with internalizing symptoms among children with moderate to high emotion regulation difficulties (DERS > 84), including those with extreme regulation difficulties (DERS > 123). In contrast, paternal attachment anxiety and avoidance were related only within a narrower emotion regulation range (DERS 68-123), and their associations diminished at higher levels. Maternal attachment avoidance was not significantly associated with internalizing symptoms. These findings underscore the interactive role of parent-specific attachment and emotion regulation in internalizing symptoms and highlight the potential clinical value of tailoring interventions to children's relational and regulatory profiles.