Date of Award:


Document Type:


Degree Name:

Doctor of Philosophy (PhD)



Committee Chair(s)

Michael P. Twohig


Michael P. Twohig


Michael E. Levin


Timothy A. Shahan


Tyson S. Barrett


Timothy Slocum


Cognitive-behavioral therapy that includes exposure, or intentionally and systematically confronting feared situations, is the gold standard psychological treatment for obsessive-compulsive disorder. However, less than half of those who begin this treatment are considered to have recovered from their disorder at the end of treatment, and this number is even smaller in the months following the end of treatment. Leading theories regarding how treatment changes occur focus on reducing fear, and they do not include “voluntary” (i.e., operant) behaviors, such as avoidance, that are key features of the disorder. Acceptance-based approaches to exposure do not focus on fear reduction, but directly focus on changing “voluntary” behaviors. Combining these two perspectives could lead to a better understanding of how exposure works and, ultimately, lead to more effective and long-lasting psychological treatments for obsessive-compulsive disorder.

The current study investigated whether accepting distress or attempting to reduce distress during exposure for intrusive thoughts led to different outcomes and whether they led to these outcomes in different ways. Participants with intrusive thoughts were randomized to three groups, Acceptance (n = 23), Regulation (n = 20), and Control (n = 21), and completed two sessions 1week apart. Participants in the Acceptance and Regulation groups completed a 30-minute exposure at session 1 and 6 days of 10-minute exposures at home; Control participants watched videos of the same lengths. Self-report questionnaires, measures of behavior, self-ratings, and physiological data were collected at both sessions.

Results showed that Acceptance and Regulation groups decreased on measures of obsessive-compulsive symptom severity, rituals performed, self-rated distress, and skin conductance levels. Acceptance showed lower skin conductance and a statistical trend toward greater self-rated willingness to experience distress than Regulation, as well as greater psychological flexibility than Control. There were no between group differences in the number of exposure tasks completed during a behavioral test, psychological inflexibility, valued living, or heart rate. This study suggests that psychological flexibility and willingness to experience distress may paradoxically lead to decreased physiological arousal, findings which may inform future research and treatment approaches.



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