Here is a passage from an article by Shedler that surveys all the research on psychodynamic. This part is about personality disorders.

Findings concerning personality disorders are particularly intriguing. A recent study of patients with borderline personality disorder ( Clarkin, Levy, Lenzenweger, & Kernberg, 2007) not only demonstrated treatment benefits that equaled or exceeded those of another evidence-based treatment, dialectical behavior therapy ( Linehan, 1993), but also showed changes in underlying psychological mechanisms (intrapsychic processes) believed to mediate symptom change in borderline patients (specifically, changes in reflective function and attachment organization; Levy et al., 2006). These intrapsychic changes occurred in patients who received psychodynamic therapy but not in patients who received dialectical behavior therapy.
Such intrapsychic changes may account for long-term treatment benefits. A newly released study showed enduring benefits of psychodynamic therapy five years after treatment completion (and eight years after treatment initiation). At five-year follow-up, 87% of patients who received “treatment as usual” continued to meet diagnostic criteria for borderline personality disorder, compared with 13% of patients who received psychodynamic therapy ( Bateman & Fonagy, 2008). No other treatment for personality pathology has shown such enduring benefits.