Vander Lugt, A. A. (2011). Evaluating process variables in acceptance and commitment therapy (Unpublished doctoral dissertation). University of North Texas, Texas.
Acceptance and commitment therapy (ACT) was developed to specifically target experiential avoidance (EA) rather than any specific diagnostic category. A functional ACT manual was presented and used to treat diagnostically diverse clients in a large sliding fee-for-service training clinic. A multiple baseline across participants and behaviors research design was used to evaluate session-by-session changes in EA, values identification, valued action, and clinical distress. The Acceptance and Action Questionnaire-2 (AAQ2), Valued Living Questionnaire (VLQ), and Outcome Questionnaire (OQ-45) were given to measure processes and outcomes given the functional ACT model presented in the introduction to the paper. Baseline included the Structured Clinical Interview for DSM-IV Axis I and II Disorders given across 2-5 50-minute sessions. The treatment phase consisted of 7-10 50-minute sessions. Participants were 10 clients. Four participants completed sufficient treatment sessions (4-9) to test the study hypotheses. Participants generally improved across time, but most improvements could not be attributed to the functional application of ACT due to changes during baseline for AAQ, VLQ-Consistency, and OQ-45. VLQ-Importance significantly improved for all participants given ACT.