Adaptation of IPT to Borderline Personality Disorder: Efficacy and Predictive Factors

Purpose: According to literature data and treatment guidelines of the American Psychiatric Association (APA, 2001, 2005), borderline personality disorder (BPD) can be successfully treated with combination of psychotherapy and pharmacotherapy. More recently, the British guidelines proposed by the National Institute for Health and Clinical Excellence (NICE, 2009) confirmed the key role of psychotherapy in the treatment of this disorder. To date, different models of psychotherapy have been tested in samples of BPD patients. Markowitz proposed an adaptation of the standard model of IPT for depression, in order to address the complexity and peculiar characteristics of BPD patients (IPT-BPD, 2005, 2007, 2012). In this adaptation BPD is conceptualized as a mood-inflected chronic illness similar to dysthymic disorder but with sporadic outburst of anger. The aim of our study is to investigate whether combined therapy with antidepressant and IPT-BPD is superior to single pharmacotherapy in a group of patients with a DSM-IV-TR diagnosis of BPD and to identify clinical and demographic predictors of response to combined therapy in this sample. Methods and results: We assessed the efficacy of the adaptation of IPT in a randomized controlled trial. IPT-BPD was provided to a sample of BPD consecutive outpatients in combination with the SSRI fluoxetine (20-40 mg/day) for 32 weeks. Combined treatment was compared with single pharmacotherapy (fluoxetine 20-40 mg/day). Remission rates and efficacy on global symptoms did not differ significantly between subgroups, but combined therapy with IPT-BPD was found superior to fluoxetine alone concerning a few core symptoms of the disorder (interpersonal relationships, impulsivity, and affective instability), anxiety symptoms, and subjective quality of life (psychological and social functioning). We also explored the following characteristics as putative predictive factors in the sample of BPD outpatients: demographic (age, gender), clinical (family psychiatric history, onset of the disorder, severity of core BPD symptoms, severity of depression and anxiety), and functional (social-occupational functioning). Two factors were significantly and independently related to the CGI-Improvement rate: severity of BPD symptoms and level of social-occupational functioning at baseline. BPD patients with higher severity of core symptoms are more likely to experience improvement after combined treatment with SSRI and IPT-BPD. It is important to notice that the predictive factor is severity of specific BPD symptoms (not general or anxious-depressive symptoms). This finding suggests that IPT-BPD has relatively specific effects on BPD psychopathology, in line with the purpose of this format. Conclusions: Initial data indicate that adapted IPT is a useful approach to treatment of BPD, a disorder with prominent relational problems. Investigation of predictors of response to this model of psychotherapy can contribute to define criteria for more individualized interventions. Data presented in this paper are part of the research findings obtained in the last ten years by the Italian Society of IPT.