For decades we have known that therapeutic working alliance is a key contributor to client engagement and positive outcomes in therapy. However, we have made little progress in narrowing down its determinants, which is critical in supporting trainees to optimize such alliance. We make a case for the value of incorporating social psychological frameworks into models of alliance and explore the role of social identity processes in the development of therapeutic alliance.

Across two studies, over 500 psychotherapy clients completed validated measures of alliance, social identification with their therapist, positive therapy outcomes, and a range of client and therapist characteristics.

Social identification strongly predicted alliance in both samples, whereas client and therapist characteristics showed few such associations. Alliance mediated the relationship between social identification and positive therapy outcomes. In addition, we found evidence that (a) personal control is a key psychological resource in therapy that arises from social identification, and (b) therapists who engage in identity leadership (i.e., who represent and build a social identity that they share with clients) are more likely to foster social identification and its downstream benefits.

These data show that social identity processes are key to the emergence of working alliance. We conclude with a discussion of how recent social identity and identity leadership interventions might be adapted to train therapists in relevant identity-building skills.