The Mediating Role of Parenting Dimensions and Mentalisation between ADHD and BPD in Adolescents: A Cross-Sectional Study

Background: Attention-deficit/hyperactivity disorder (ADHD) and borderline personality disorder (BPD) share overlapping features such as impulsivity and emotional dysregulation, yet their co-occurrence in adolescents is rarely examined outside Western settings. In Southeast Asia, where parenting practices and cultural norms may shape developmental pathways differently, this relationship remains underexplored. Evidence is also limited on how parenting dimensions and mentalisation contribute to the ADHD–BPD link. This study addresses these gaps by examining Malaysian adolescents, providing cross-cultural insights into early psychosocial risk factors that may inform targeted interventions. Methods: A cross-sectional study was conducted from March to July 2025 in three government secondary schools in urban Selangor, Malaysia, involving 126 adolescents aged 14 to 16 years. ADHD symptoms were assessed using the parent-rated Swanson, Nolan, and Pelham Rating Scale–Fourth Edition (SNAP-IV), while adolescents completed a sociodemographic questionnaire, the Borderline Symptom List–23 (BSL-23), the Parental Bonding Instrument (PBI), and the Mentalisation Scale–12 (MentS–12). Descriptive statistics and bivariate correlations were conducted using SPSS version 30, and mediation analyses were performed using Jamovi version 2.6.26. Results: Clinically significant ADHD and BPD symptoms were present in 10.3% and 15.9% of adolescents, respectively. ADHD and BPD symptoms were moderately correlated ( r  = 0.33, p  < .001). Mediation analyses revealed that paternal parenting dimensions and lower adolescent mentalisation capacity significantly mediated the association between ADHD and BPD symptoms. Conclusions: These findings suggest that paternal parenting and mentalisation capacity may play important roles in the co-occurrence of ADHD and BPD symptoms among adolescents. Longitudinal research is warranted to clarify the causal pathways involved. Trial registration: Not applicable.