Physiological, behavioral, and self-report outcomes of acceptance- and regulation-based exposure for intrusive thoughts

Leading theories regarding the mechanisms of exposure for OCD focus on Pavlovian fear reduction more than operant processes. Acceptance-based exposure directly targets operant behavior. Integrating these perspectives could lead to a more robust understanding of mechanisms of change in exposure and more effective and enduring treatments. The current study investigated acceptance and regulation of distress during exposure. Participants with intrusive thoughts were randomized into three groups, Acceptance (n = 23), Regulation (n = 20), and Control (n = 21), and completed two behavioral avoidance tests (BATs) 1 week apart. Active conditions completed a 30-min exposure plus 6 days of 10-min exposures at home; Control participants watched videos of the same durations. Self-report measures were collected at both sessions, and behavioral, subjective, and physiological repeated measures data were collected during both BATs. Compared to Control, active conditions decreased OCD symptom severity, rituals, and skin conductance levels, while Acceptance showed lower skin conductance levels than Regulation and Control. Acceptance showed greater willingness and psychological flexibility than Control, while Regulation did not. Results support theorized mechanisms of change in acceptance-based exposure and suggest willingness to experience distress may paradoxically lead to decreased physiological arousal, which has important implications for treatment and future research.