Combining Acceptance and Commitment Therapy With Exposure and Response Prevention to Enhance Treatment Engagement in Obsessive-Compulsive Disorder

1. BACKGROUND AND SIGNIFICANCE.

The most effective psychological treatment for Obsessive-Compulsive Disorder (OCD) is Exposure and Response Prevention (ERP), which entails confronting obsessional triggers (i.e., exposure) and resisting urges to ritualize (response prevention). Although successful, these techniques are challenging and provoke high levels of anxiety. This may contribute to the fact that between 25% and 50% of patients with access to ERP refuse treatment, drop out prematurely, or do not adhere to the treatment instructions and show attenuated response. Given the effectiveness of ERP techniques, developing ways to make them more tolerable and increase patient adherence, while not compromising therapeutic integrity, is an important next step in OCD treatment research. Recent investigations have addressed whether adding medications, cognitive therapy, or motivational Interviewing to ERP improves outcome and adherence; yet to date, no consensus has emerged regarding the degree to which these combination treatments are more effective than ERP monotherapy. Acceptance and Commitment Therapy (ACT), which has recently been studied for OCD, offers new hope for addressing the tolerability and adherence issues with ERP. Specifically, ACT uses acceptance and mindfulness processes to foster a willingness to experience unwanted inner experiences (e.g., obsessional thoughts, anxiety). These acceptance and mindfulness processes are consistent with ERP, but they are hypothesized to increase engagement in exposure exercises beyond ERP alone. There is evidence for this claim from a randomized trial which demonstrated that ACT, without in-session exposure, had clinical response rates in the 55-65% range at posttreatment and three month follow-up using an intent to treat analysis. Additionally, drop-out and refusal rates were low at 12.2% and treatment acceptability at posttreatment was near the maximum on the scale 4.3 out of 5. In this study, for experimental reasons, ACT did not include in-session ERP. However, the most theoretically and practically consistent use of ACT for OCD is as a context from which to conduct exposure therapy or ERP. While ACT focuses on processes (e.g., acceptance, defusion, values) that are distinct from those involved in ERP (e.g., habituation, cognitive change), an important goal of both treatments is to broaden the patient's engagement with feared stimuli. In fact, ACT procedures have been shown to increase involvement in difficult activities, including participating in exposure therapy for anxiety disorders and willingness to experience unwanted obsessive thoughts. Thus, building ACT techniques into ERP is likely to help patients (a) engage in ERP tasks, (b) confront high levels of anxiety without using escape/avoidance strategies, and (c) resist rituals. The aim of the proposed study is to evaluate whether integrating ACT increases the acceptability, tolerability, and adherence with ERP techniques relative to ERP without ACT. 2. STUDY DESIGN AND HYPOTHESES.

Fifty-eight adults with a DSM-IV diagnosis of Obsessive-Compulsive Disorder (OCD) received 16 twice-weekly sessions (2 hours per session) of either ERP with the inclusion of ACT techniques (ERP+ACT; n = 30) or ERP alone (n = 28). Assessments using interviews, self-report questionnaires, and behavioral observations were conducted at pre- and post-test, and at 6 month follow-up. Specific hypotheses were: 1) Patients receiving ERP+ACT will report greater treatment acceptability, and show higher quantity and quality of completed self-directed ERP assignments, relative to patients receiving standard ERP; 2) Both ERP and ERP+ACT will lead to clinically significant reductions in OCD symptoms from pre- to post-test and from pre-test to follow-up. 3. METHODS

3a. Sample Size and Recruitment. The investigators aimed for an intent-to-treat sample of 60 adults across two sites: The Center for Clinical Research at Utah State University (USU) and the Anxiety and Stress Disorders Clinic at the University of North Carolina, Chapel Hill (UNC). Patients were recruited via advertisement of the study and via referrals from primary care and mental health providers familiar with the treatment centers. The USU Center (Twohig) and the UNC Clinic (Abramowitz) are well known research-oriented treatment clinics in their regions. USU is within a 1:30 minute drive of two million people and travel for treatment is common given the rural nature of the area. Also, no other known entity recruits participants with OCD in this area. The Raleigh-Durham-Chapel Hill area of NC is home to over one million people, and the UNC Clinic receives a steady stream of inquiries for treatment. Patient advocacy groups and associations that post research trials on the Internet were contacted to further publicize the study.

3b. Establishing Diagnoses. All diagnoses were established by trained interviewers using the Mini International Neuropsychiatric Interview (MINI).