Parent–adolescent psychological distress (in)congruence and adolescent NSSI: a dyadic response surface analysis

BACKGROUND: Non-suicidal self-injury (NSSI) represents a significant public health concern among adolescents with mood disorders. While individual psychological distress is established as a risk factor, the impact of parent-adolescent emotional congruence/incongruence on NSSI remains underexplored. This study aimed to examine the associations between adolescent and parental psychological distress and adolescent NSSI, focusing on the effects of dyadic congruence and incongruence. METHODS: The study included 147 parent-adolescent dyads (94 girls, 53 boys; mean age = 15.18 years) with adolescents diagnosed with depression or bipolar disorder. Participants completed the Depression Anxiety Stress Scale (DASS-21) and the Self-Injurious Behavior Scale. Polynomial regression analysis and response surface analysis were employed to examine the effects of congruence and incongruence in psychological distress between parents and adolescents on adolescent NSSI. RESULTS: Adolescent psychological distress was positively associated with NSSI frequency (depression: r = 0.38, p < 0.001; anxiety: r = 0.42, p < 0.001; stress: r = 0.31, p < 0.001). Response surface analyses revealed that emotional incongruence between parents and adolescents significantly predicted higher levels of NSSI for all three dimensions of psychological distress. For anxiety specifically, a U-shaped curvilinear relationship emerged (a₄=0.29, p < 0.001), indicating that extreme incongruence in either direction was particularly detrimental. CONCLUSION: The current study highlights that beyond individual psychological distress, emotional incongruence between parents and adolescents represents a significant risk factor for NSSI in clinically depressed adolescents. This underscores the importance of family-based interventions that promote emotional understanding and co-regulation within parent-adolescent relationships to reduce NSSI risk in clinical populations.