The present review summarizes the current state of the art in psychotherapy processes during treatments for clients with personality disorders. We outline some methodological challenges in the discipline of process research, give a brief historical account on process research, and then focus on specific processes studied from an empirical perspective.
The current review acknowledges the centrality of the therapeutic relationship, in particular the therapeutic alliance, therapist empathy, and responsiveness in explaining outcome across treatment modalities for personality disorders. The review describes evidence from three overall and overlapping lines of inquiry that have garnered scientific interest in the past years. For emotional change (regulation, awareness, and transformation), socio-cognitive change (mentalizing, meta-cognition, and interpersonal patterns), and increase in insight and change in defense mechanisms, evidence is moderate to strong for these processes to contribute to healthy change in treatments for personality disorders, in particular borderline personality disorder. Avenues of future studies are outlined.