Does Mismatching Matter? A Systematic Review Into the Impact of Therapist‐Client Personality Similarity on the Therapeutic Alliance

ABSTRACT Purpose The therapeutic alliance (TA) can be conceptualised in terms of three interrelated elements: (a) agreement between therapist and client about the goals of the treatment, (b) agreement between therapist and client about the necessary tasks to achieve the goals, and (c) a bond between therapist and client. The aim of this review was to systematically identify and review relevant studies that have explored the association between client‐therapist personality similarity on the therapeutic alliance. Method We systematically searched the PsycINFO, MEDLINE, Web of Knowledge, COPAC, CINAHL, and Science Direct databases from 1960 to 2013. Of the 105 articles identified, six met inclusion criteria for the review. Of the six studies, four were conducted in the United States, one in Israel and one in the Netherlands. Results One study found that clients reported a stronger bond with the therapist when client‐therapist personality similarity was greater. Five out of the six studies reviewed found support for the role of dissimilarity whereby differences between client and therapist were beneficial. Findings appear to differ depending on the characteristic examined, the specific component of TA, gender and whether the measure of TA is client or therapist reported. Conclusions This review has highlighted an under‐researched area of inquiry. Initial findings suggest that the relationship between therapist‐client personality (dis)similarity and TA warrants further attention. Key methodological and analytical differences across studies were also identified, along with key challenges for future research.