Abstract
BACKGROUND: The mentalization theory posits that interpersonal difficulties and maladaptive personality traits develop from an insecure attachment pattern with one's caregiver and corresponding deficits in mentalizing-the ability to understand others' and one's own mental states. Mentalizing deficits have been theorized as the basis for all psychopathology, with the paradigmatic case being Borderline Personality Disorder. Nevertheless, developments in the personality field indicate personality pathology is best represented dimensionally, and such a proposal was outlined by the Alternative DSM-5 Model for Personality Disorders (AMPD). Despite evidence linking the mentalization theory to personality disorders, however, it has yet to be applied to Criterion B of the AMPD. The aim of the present study was to evaluate the moderating role of mentalizing in the relation between attachment and Criterion B maladaptive trait function in a sample of undergraduates. We hypothesized a model in which: (1) attachment insecurity would be positively associated with the Negative Affectivity, Antagonism, and Disinhibition personality domains; (2) mentalizing ability would be negatively associated with these domains; and, (3) there would be an interaction effect between attachment and mentalizing when predicting these same domains. METHODS: Personality domains were measured dimensionally via the Personality Inventory for DSM-5 (PID-5-SF), while the dependence and avoidance domains of attachment were assessed via the Relationship Questionnaire (RQ). Mentalizing ability was tapped by the Movie for the Assessment of Social Cognition (MASC). The AMPD personality domains and trait facets were examined as dependent variables; attachment dependence, attachment avoidance, and overall mentalizing ability were entered as independent variables; and interaction terms between mentalizing and each attachment dimension were used to test moderation via MANCOVAs. RESULTS: Consistent with expectations, results indicated overall mentalizing moderated the relation between attachment avoidance and Negative Affectivity. Posthoc analyses revealed similar effects on the relations between attachment avoidance and the Emotional Lability, Hostility, and Perseveration trait facets; however, there were no significant moderation findings related to attachment dependence. CONCLUSIONS: These results support the mentalization theory's application to Criterion B of the AMPD, particularly in relation to the links between Negative Affectivity and borderline-related traits, and encourage future research of dimensional maladaptive personality. They further bolster support for understanding maladaptive personality as a dimensional construct.