Effects of Acceptance and Commitment Therapy on Impulsive Decision Making

139 Pages·2016·1.78 MB·English

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All Graduate Theses and Dissertations Graduate Studies
5-2016
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Kate L. Morrison
Utah State University
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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 ............................................................................................... 50
Conclusion ......................................................................................................... 52

REFERENCES .............................................................................................................. 53

APPENDICES ............................................................................................................... 64

Appendix A: Recruitment Materials ................................................................ 65
Appendix B: Measures .................................................................................... 68
Appendix C: ACT Treatment Manual ............................................................. 78
Appendix D: Individual Data ........................................................................... 108

CURRICULUM VITAE ................................................................................................ 117