Fluctuations in therapist responsiveness facing clients with borderline personality disorder: Starting therapy on the right foot.

Objective: The present paper focuses on therapist responsiveness during the initial therapy session with clients with borderline personality disorder (BPD), aiming to analyze therapist responsiveness at short intervals during the initial session and determine if it can predict therapeutic alliance from both therapist and client viewpoints.

Method: A sample of 47 clients participated in the study for 10 sessions of therapy. Therapeutic alliance from therapists' and clients' perspectives was rated after each session; external raters assessed therapist responsiveness during the initial session. Multiple linear regression models and linear mixed models with backward variable selection based on AIC were run to analyze whether specific therapist behaviors during session one predicted therapeutic alliance rated from therapists' and clients' perspectives.

Results: The results indicate that therapists normalizing and validating clients' experiences during the first session are crucial for establishing therapeutic alliance for BPD clients; however, for therapists, the increase in variability of emotions verbalized by clients during the initial session negatively impacts therapeutic alliance.

Conclusion: The study contributes to further understand the impact of therapists' behavior at the beginning of therapy with BPD clients. Therapist responsiveness is crucial for therapy outcome but is methodologically challenging; therefore, efforts in this direction should be pursued.