Sympathetic nervous system synchrony: An exploratory study of its relationship with the therapeutic alliance and outcome in couple therapy.

: In previous research, we found that sympathetic nervous system synchrony, measured via electrodermal activity (EDA), occurs between participants at the start of couple therapy. The aim now was to test whether this synchrony changes during the therapy process, and how any changes may be related to clients' and therapists' evaluations of the working alliance, and the outcome of therapy. Twelve different couple therapy processes were analyzed (24 clients, plus 10 therapists, working in pairs; hence, 4 persons per session) using EDA concordance indices and questionnaires (Outcome Rating Scale, Session Rating Scale, and Clinical Outcomes in Routine Evaluation-Outcome Measure). EDA synchrony between the couples increased from the beginning to the end of therapy. This seemed to be connected to a positive linear trend in female clients' well-being during the therapy process. There were no statistically significant changes in the EDA synchrony between the cotherapists, or between the clients and the therapists. We found specific changes in the EDA synchrony to be related to changes in the therapeutic alliance, and/or changes in the clients' well-being. Heightened EDA synchrony was frequently related to a better outcome; nevertheless, there was one instance in which decreasing synchrony seemed to be more beneficial. It appears that couple therapy can bring spouses closer together also on a physiological level, which could be especially important for the well-being of women. (PsycINFO Database Record (c) 2019 APA, all rights reserved).