A Systematic Review of Therapist Mentalizing: Characteristics, Measurement, Construct Validity and Outcome

Abstract This paper reports on a pre-registered systematic review (PROSPERO; REF: CRD42023472339) of the role of therapists’ mentalizing capacity in psychotherapy processes. Studies were reviewed to address the following research questions: (i) what are the characteristics of studies that have investigated therapists’ mentalizing; (ii) what measurement tools are used to assess therapists’ mentalizing; (iii) what is the evidence of construct validity of these assessment tools; and (iv) what is the evidence of association between therapists’ mentalizing and patient outcome following psychotherapy. Studies conducted after 1991 that employed a quantitative design and measured therapists’ mentalizing were included. Three databases were searched on 14th February 2025: MEDLINE ® , PsychINFO and EMBASE. The identified studies were appraised for quality and data was extracted for narrative synthesis. Fourteen articles were included in this review. There was large heterogeneity across studies in terms of design, measurement of mentalizing and treatment modalities employed. Preliminary evidence suggested therapist mentalizing may both influence psychotherapy outcome across different therapeutic approaches and be associated with therapist wellbeing. Despite numerous limitations observed in this exploratory research, therapist mentalizing may play an important role in psychotherapy change processes. Implications for how therapist mentalizing could be optimised to improve therapeutic effectiveness and to mitigate against the impacts of stressful working environments are considered, along with recommendations for future research.