Diana Diamond, Kenneth N. Levy, John F. Clarkin, Melitta Fischer-Kern, Nicole M. Cain, Stephan Doering, Susanne Hörz, Anna Buchheim

We investigated attachment representations and the capacity for mentalization in a sample of adult female borderline patients with and without comorbid narcissistic personality disorder (NPD). Participants were 22 borderline patients diagnosed with comorbid NPD (NPD/BPD) and 129 BPD patients without NPD (BPD) from 2 randomized clinical trials. Attachment and mentalization were assessed on the Adult Attachment Interview (AAI; George, Kaplan, & Main, 1996). Results showed that as expected, compared with the BPD group, the NPD/BPD group was significantly more likely to be categorized as either dismissing or cannot classify on the AAI, whereas the BPD group was more likely to be classified as either preoccupied or unresolved for loss and abuse than was the NPD/BPD group. Both groups of patients scored low on mentalizing, and there were no significant differences between the groups, indicating that both NPD/BPD and BPD individuals showed deficits in this capacity. The clinical implications of the group differences in AAI classification are discussed with a focus on how understanding the attachment representations of NPD/BPD patients helps to illuminate their complex, contradictory mental states.