Introduction: One of the earliest theoretical assumptions of Functional Analytic Psychotherapy (FAP) that has not yet been tested was that attention to the client's clinically relevant behaviours (CRBs) would be of great importance in the therapist's ability to contingently respond to the occurence of such behaviours (Kohlenberg & Tsai, 1991). Although recent studies on other therapy forms have only employed self-report measurements, they demonstrated a beneficial effect of the therapist's practice of mindfulness on attention during session (Hunt et al., 2022), and provide a potential avenue for testing the aforementioned assumption. The objective of this study is to analyse the effect of mindfulness practice before session on the therapist’s ability to identify CRBs and on this account also test the assumption that better awareness to CRBs transaltes into more efficient contingent responses on behalf of the therapist. We hypothesise that, compared to control, in the sessions when therapists practiced mindfulness beforehand, therapists will miss fewer of the clients' clinically relevant behaviours and will deliver more efficient contingent responses to their occurence.

Method: In this triple-blind study, data collected during 5 therapy sessions across 8 single-case studies, will be analysed by two independent raters who will code for clients and therapists behaviours.

Results: At the time of the submission of this abstract, the study has already been pre-registered (Pătru et al., 2025). It is anticipated that data collection and analysis will be finalized ahead of the conference, enabling a full presentation of the study's findings.

Paul Alexandru Patru is a Master’s student at the Clinical Psychology, Psychological Counseling and Psychotherapy Master programme at the Psychology and Educational Sciences Faculty of the Babeș- Bolyai University from Cluj-Napoca. He has been trained in Functional Analytic Therapy by FAP certified trainers for the last 2 years and is currently in the process of becoming a FAP certified therapist. Financial support for the present study is granted through a research scholarship by the Babeș-Bolyai University of Cluj-Napoca.