Implicit and Explicit Mentalizing Deficits in Adolescent Inpatients: Specificity and Incremental Value of Borderline Pathology

Research has demonstrated mentalizing impairment associated with borderline personality disorder (BPD) in adolescents. However, mentalizing performance in adolescents with BPD has never been compared to that of psychiatric control and healthy control adolescents simultaneously. The present study aimed to (a) compare implicit and explicit mentalizing, and hypermentalizing errors in implicit mentalizing, across youth with BPD and psychiatric and healthy controls, and (b) evaluate the association of borderline features with mentalizing deficits over and above internalizing and externalizing. Psychiatric inpatients with BPD (n = 139), inpatient psychiatric controls (n = 310), and healthy adolescents (n = 134) completed two mentalizing tasks, an interview assessing BPD, and measures of psychopathology. Results showed that BPD specificity could be demonstrated only for implicit mentalizing and hypermentalizing. Explicit mentalizing deficits did not differ between BPD and psychiatric control groups. Borderline features had unique associations to implicit mentalizing and hypermentalizing, over and above internalizing and externalizing.