Date of Award


Degree Type


Degree Name




First Advisor

Antonio Pascual-Leone


depression, emotion focused therapy, experiential therapy, process, psychotherapy, sudden gains




The present study involves the first attempt to identify sudden gains in a sample of clients undergoing experiential treatment for depression. "Sudden gains," or sudden, substantial improvements in depressive symptomology between consecutive psychotherapy sessions, have been repeatedly observed among depressed clients in psychotherapy. Approximately 45% of depressed clients appear to experience sudden gains, and those clients who do experience sudden gains appear to have significantly better treatment outcomes than those who do not (Tang et al., 2007). While there exists some evidence for the generalizability of sudden gains across treatment modalities (e.g., Kelly et al., 2007; Present et al., 2008), to date there have been no published investigations demonstrating that sudden gains occur in experiential therapies. An archival videotape data sample of therapist-client dyads was drawn from a larger subject pool originally recruited for a clinical trial at the York University Psychotherapy Research Clinic (Goldman, Greenberg, & Angus, 2006). Thirty-six dyads were identified as appropriate for inclusion in the present study. These cases were then coded moment-by-moment using selected psychotherapy process measures; this data was added to existing archival outcome data for analysis. Results of the study revealed that sudden gains were present in the data set. Consistent with previous investigations (e.g., Tang et al., 2007), sudden gain onset was found to be associated with a significant increase in the number of cognitive changes experienced by clients. Sudden gain onset was also found to be associated with deepened client experiencing, and the observed changes in both of these constructs were found to be correlated. The bulk of the dramatic symptom decrease associated with sudden gains (74.89%) was found to occur within the session preceding the sudden gain. During this critical session, therapists of clients who experienced sudden gains were found to be significantly more likely to focus on unmet client needs prior to sudden gain onset, while clients were significantly more likely to express "productive" emotions (e.g., assertive anger; as identified by Pascual-Leone & Greenberg, 2007). Both the research and clinical implications of the above findings, some of which appear to challenge existing assumptions regarding sudden gains, are discussed.