Multimodal Analysis of Temporal Affective Variability Within Treatment for Depression

Objective: Affective flexibility, the capacity to respond to life’s varying environmental changes in a dynamic and adaptive manner, is considered a central aspect of psychological health in many psychotherapeutic approaches. The present study examined whether affective two-dimensional (i.e., arousal and valence) temporal variability extracted from voice and facial expressions would be associated with positive changes over the course of psychotherapy, at the session, client, and treatment levels. Method: A total of 22,741 mean vocal arousal and facial expression valence observations were extracted from 137 therapy sessions in a sample of 30 clients treated for major depressive disorder by nine therapists. Before and after each session, the clients self-reported their level of well-being on the outcome rating scale. Session-level affective temporal variability was assessed as the mean square of successive differences between consecutive two-dimensional affective measures. Results: Session outcome was positively associated with temporal variability at the session level (i.e., within clients, between sessions) and at the client level (i.e., between clients). Importantly, these associations held when controlling for average session- and client-level valence scores. In addition, the expansion of temporal variability throughout treatment was associated with steeper positive session outcome trajectories over the course of treatment. Conclusions: The continuous assessment of both vocal and facial affective expressions and the ability to extract measures of affective temporal variability from within-session data may enable therapists to better respond and modulate clients’ affective flexibility; however, further research is necessary to determine whether there is a causal link between affective temporal variability and psychotherapy outcomes.