Cortisol Synchrony in Psychotherapy for Major Depressive Disorder

Introduction: Accumulating research emphasizes the role of interpersonal coordination in arousal levels, which may manifest as cortisol synchrony, in interpersonal interactions. While the role of cortisol has been investigated in psychotherapy, cortisol synchrony and its characteristics and effect on treatment progress remain a relatively unexplored area. This study aims to explore the existence of distinct patterns of cortisol coordination throughout psychotherapy and test the associations of different coordination patterns with patients' pre-treatment characteristics and treatment progress measures. Methods: Fifty patient–therapist dyads participated in 16 weeks of psychodynamic treatment for major depressive disorder. Salivary cortisol samples were collected before and after each session at four time points. Self-report questionnaires and treatment session video-coding were used to characterize and differentiate between patterns of cortisol coordination. Results: Three patterns of cortisol coordination were identified: synchronized, unsynchronized and stable-therapist. These patterns differed in patient characteristics and treatment progress measures in that patients exhibiting a synchronized pattern tended to be more anxious and dominant in their relationships and were more prone to withdrawal ruptures. Conclusions: Results provide novel evidence regarding variability in patient–therapist cortisol patterns and its putative associations with treatment progress.