Date of Award:


Document Type:


Degree Name:

Doctor of Philosophy (PhD)




Michael P. Twohig


Delay discounting is a measure of impulsive decision making that is associated with different forms of problem behavior. This study examined the transdiagnostic effect of Acceptance and Commitment Therapy (ACT) on delay discounting in a community sample. Forty adults were randomized into eight individual sessions of ACT or an inactive control. Participants completed pre-, mid-, and post-assessments for delay discounting, psychological flexibility, distress tolerance, overall psychological symptoms, behavior change, and valued living. Data were analyzed with multilevel modeling of growth curves. Significant interaction effects of time and condition were present for psychological flexibility, distress tolerance, psychological symptoms, and the obstruction subscale of valued living. No significant interaction effect was found for two delay discounting tasks nor the progression subscale of valued living. The ACT condition had a significantly larger reduction of problem behavior at post-, but not mid-assessment. Treatment was provided in a competent and ACT-consistent manner and was rated as highly satisfactory by treatment completers. The results support use of ACT as a transdiagnostic treatment. The lack of changes in delay discounting are in contrast to previous research. The clinical implications of delay discounting need to be explored further.



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