Effects of Acceptance and Commitment Therapy on Impulsive Decision Making
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Utah State University DigitalCommons@USU All Graduate Theses and Dissertations Graduate Studies 5-2016 Effects of Acceptance and Commitment Therapy on Impulsive Decision Making Kate L. Morrison Utah State University Follow this and additional works at: https://digitalcommons.usu.edu/etd Part of the Psychology Commons Recommended Citation Morrison, Kate L., "Effects of Acceptance and Commitment Therapy on Impulsive Decision Making" (2016). All Graduate Theses and Dissertations. 5069. https://digitalcommons.usu.edu/etd/5069 This Dissertation is brought to you for free and open access by the Graduate Studies at DigitalCommons@USU. It has been accepted for inclusion in All Graduate Theses and Dissertations by an authorized administrator of DigitalCommons@USU. For more information, please contact [email protected]. EFFECTS OF ACCEPTANCE AND COMMITMENT THERAPY ON IMPULSIVE DECISION MAKING by Kate L. Morrison A dissertation submitted in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY in Psychology Approved: Michael P. Twohig, Ph.D. Michael E. Levin, Ph.D. Major Professor Committee Member Gregory J. Madden, Ph.D. Amy L. Odum, Ph.D. Committee Member Committee Member Timothy A. Slocum, Ph.D. Mark McLellan, Ph.D. Committee Member Vice President for Research and Dean of the School of Graduate Studies UTAH STATE UNIVERSITY Logan, Utah 2016 ii Copyright © Kate L. Morrison 2016 All Rights Reserved iii ABSTRACT Effects of Acceptance and Commitment Therapy on Impulsive Decision Making by Kate L. Morrison, Doctor of Philosophy Utah State University, 2016 Major Professor: Michael P. Twohig, Ph.D. Department: Psychology 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 iv 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. (138 pages) v PUBLIC ABSTRACT Effects of Acceptance and Commitment Therapy on Impulsive Decision Making Kate L. Morrison For some people, decision making is more often influenced by immediate gratification, rather than what is best for them in the long term. This study intended to change how those people made decisions, in order to help them live meaningful lives. This was done through eight sessions of a treatment called Acceptance and Commitment Therapy (ACT; in comparison to no treatment). Forty adults were randomly assigned to either treatment or a no treatment control. The treatment did not change the way people responded on the decision making measures, although the treatment reduced problematic behaviors and obstacles to living a meaningful life. The treatment increased openness and flexibility to emotions, thoughts, and bodily sensations that can influence decision making. Treatment also increased overall well-being. Taken together, the results suggest that ACT is a useful treatment to help people change behaviors that are a problem for them and can increase their quality of life. However, these changes did not occur in the expected manner. vi ACKNOWLEDGMENTS I would like to thank Dr. Michael Twohig not only for his help on this project, but also for years of research and professional guidance. My graduate school experience has been life changing and his role as my mentor is one of the main reasons for that. I would also like to thank the wonderful team of individuals who made this project possible. Thanks to my committee members, Gregory Madden, Amy Odum, Timothy Slocum, and Michael Levin for their assistance in designing and refining this study and document. Jodi Siri was in a less glamorous, but essential role of research assistant for this study. Completing the study without her would have been extremely difficult. Jonathan Friedel and Jillian Rung were critical collaborators in collecting, analyzing, and understanding the delay discounting data. Brooke Smith and Clarissa Ong generously provided their time as superb therapists. Eric Lee and Clarissa Ong spent tiresome hours coding for treatment adherence. Thomas Ledermann and Sarah Schwartz provided highly appreciated statistical explanations and support. Thank you to my lab mates who were always willing to brainstorm, problem solve, and share in the joys of doing research. I would like to thank my patient and caring partner, Mac Gilbert. With his encouragement to eat, sleep, and exercise, I stayed somewhat healthy during this process. I would especially like to thank my family for their endless support in my educational pursuits and for always providing comic relief when needed. We absolutely earned this degree together. Finally, I would like to thank the people who participated in this study. They vii devoted a portion of their lives to better the field of clinical psychology and, for that, I am forever grateful. Kate L. Morrison viii CONTENTS Page ABSTRACT ................................................................................................................... iii PUBLIC ABSTRACT ................................................................................................... v ACKNOWLEDGMENTS ............................................................................................. vi LIST OF TABLES ......................................................................................................... ix LIST OF FIGURES ....................................................................................................... x CHAPTER 1. INTRODUCTION ............................................................................................. 1 2. REVIEW OF THE LITERATURE ................................................................... 3 Delay Discounting ............................................................................................. 3 Proposed Intervention ........................................................................................ 7 3. METHODS ........................................................................................................ 10 Design ................................................................................................................ 10 Participants ......................................................................................................... 11 Procedures .......................................................................................................... 11 Conditions .......................................................................................................... 12 Treatment Adherence ......................................................................................... 13 Measures ............................................................................................................ 15 Statistical Analyses ............................................................................................ 20 4. RESULTS .......................................................................................................... 26 Participant Characteristics ................................................................................. 26 Treatment Adherence ......................................................................................... 30 Problem Behavior Frequency ............................................................................ 31 Delay Discounting Outcomes ............................................................................ 31 Clinical Outcomes .............................................................................................. 35 Addressing Lack of Power ................................................................................. 39 Treatment Satisfaction ....................................................................................... 40 ix 5. DISCUSSION .................................................................................................... 41 Transdiagnostic Application .............................................................................. 41 Delay Discounting ............................................................................................. 42 Clinical Applications ......................................................................................... 47 Limitations ......................................................................................................... 48 Future Directions ..............................................................................................