Cortisol interdependence during psychotherapy in major depressive disorder.

The current study explored cortisol interdependence between patients and therapists during psychotherapy, the possible moderating effect of patient alliance ratings on this interdependence, and the associations between cortisol interdependence and treatment outcome. While cortisol interdependence was explored in other interpersonal contexts, its presence in psychotherapy has remained unexplored. We hypothesized that (a) patients' and therapists' cortisol levels at pre-session will predict their own and their partner's subsequent cortisol levels at post-session, (b) patient ratings of their relationship with their therapists will moderate these partner effects, and (c) cortisol interdependence will be associated with better treatment outcome. Fifty dyads undergoing 16 weeks of psychodynamic treatment for major depressive disorder participated in this study. Patient-therapist salivary cortisol samples were collected at eight time points, alongside a post-session patient-rated alliance questionnaire and a symptom severity interview. For analyses we employed the actor-partner interdependence model. Results revealed that (a) patients' and therapists' cortisol levels before sessions predicted their own post-session cortisol changes. However, significant cortisol interdependence was observed in patients' pre-session cortisol levels predicting therapists' post-session cortisol levels. Furthermore, (b) poorer alliance ratings associated with more pronounced cortisol interdependence, and (c) in dyads where patient pre-session cortisol predicted therapist's post-session cortisol, a better treatment outcome was found. This study found novel evidence of cortisol interdependence in psychotherapy and is partially in line with other studies inspecting cortisol interdependence in adjacent research fields. These findings emphasize the intricate psychophysiological interactions within therapeutic relationships and their associations with treatment outcome.

Patient and Therapist In-Session Cortisol as Predictor of Post-Session Patient Reported Affect.

The importance of the role of affect in psychotherapy for major depressive disorder (MDD) is well established, but the common use of self-reported measures may limit our understanding of its underlying mechanisms. A promising predictor of patient affect is the stress hormone cortisol. To date, no studies have studied in-session changes in cortisol in psychotherapy for MDD. We investigated whether an increase in patient cortisol over the course of a session correlated with higher negative and lower positive affect. Given previous findings on healthy individuals on the contagious nature of stress, an additional aim was to examine whether these relationships are moderated by therapist cortisol. To this end, 40 dyads (including 6 therapists) provided saliva samples before and after four pre-specified sessions (616 samples). After each session, the patients provided retrospective reports of in-session affect. We found no association between patient cortisol and affect. However, increases in patient cortisol predicted negative affect when the therapists exhibited decreases in cortisol, and increases in patient cortisol predicted positive affect when the therapists showed increases. Our study provides initial evidence for the importance of the social context in the cortisol-affect relationship in MDD.