Sigal Zilcha‐Mano
INTRODUCTION: Mechanisms of change are widely assumed to be activated by the onset of treatment. This foundational premise underlies decades of psychotherapy research and guides the timing of measurement and intervention in clinical science. The present study challenges this assumption by demonstrating that one of the most well-established predictors of treatment outcome - the therapeutic alliance - not only changes before therapy begins, but that these early, pretreatment changes predict both alliance development and symptom reduction throughout treatment. METHODS: In a randomized controlled trial for depression (N = 100), the therapeutic alliance was assessed twice before patients met their therapist and weekly thereafter. RESULTS: The pretreatment change in alliance significantly predicted subsequent alliance dynamics and clinical improvement, above and beyond baseline levels. The findings remained robust even after controlling for pretreatment outcome expectations and previous treatment experience. CONCLUSIONS: These findings suggest that mechanisms traditionally viewed as the result of treatment targeting may, in fact, be antecedents. By revealing pre-treatment shifts in a mechanism once thought to be non-existent prior to patient-therapist contact, this work may challenge fundamental assumptions in clinical psychology and highlights the need to reconceptualize mechanisms of change as person-specific dynamic signatures that characterize individuals even before psychotherapy begins. Such a shift has implications for how we define, measure, and intervene on core mechanisms of human change.