Treatment of Obsessive-Compulsive Disorder and the Importance of Assessing Clinical Effectiveness

Abstract

Obsessive-compulsive disorder (OCD) is a debilitating disorder with a typically chronic course without treatment. The current thesis addresses the following research questions: The first aim is to provide an updated review of evidence-based psychological treatment for adult OCD. A traditional meta-analytic approach is combined with a systematic evaluation of the methodological quality of the included studies in order to provide recommendations for enhanced methodological stringency and study moderators of treatment outcome. These topics are addressed in Paper I. While randomized controlled trials (RCTs) can be considered the “gold standard” for treatment research, it can be argued that when evaluating a new treatment format, a pilot study followed by an effectiveness study and then a replication study is a preferable approach. The OCD-team in Helse Bergen, which is an out-patient clinic part of the specialist health care, has developed a novel treatment format of exposure based cognitive behavioral therapy where individually tailored and therapist assisted exposure and response prevention is delivered in a group format during four consecutive days. The second research aim was thus to assess to which extent OCD patients accepted the novel format, and to investigate its clinical effectiveness. Specifically changes in OCD symptoms, as well as changes in secondary outcomes like depression and work impairment, were investigated. These questions are addressed in a pilot study (Paper II) and an effectiveness study (Paper III). The third aim was to investigate if the results were replicable, which is addressed in Paper IV. Methods: Paper I includes all randomized controlled trials (RCTs) of cognitive behavioral treatment (CBT) for OCD. The term CBT was defined as treatment with CBT, cognitive therapy (CT) or exposure and response prevention (ERP). Included studies were published between 1993 and 2014 and used the interview-based Yale– Brown Obsessive-compulsive Scale as a primary outcome measure. The paper provides a systematic review and meta-analysis of the included studies, as well as an evaluation of methodological aspects by using the Psychotherapy outcome study methodology rating form. Active treatments were compared to active treatment, control, or waitlist conditions, and potential moderators were investigated with a subgroup analysis and meta-regression analyses. Paper II is a pilot study examining six patients undergoing Concentrated Exposure Treatment (cET), focusing on patients’ acceptance of treatment defined as proportion declining treatment, attrition and patients’ satisfaction; as well as clinical changes in OCD symptoms and depressive symptoms. OCD symptoms are assessed with the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) and depressive symptoms with the Beck Depression Inventory (BDI). Acceptability is assessed with clinical interviews. Paper III is a larger effectiveness study that further investigates patients’ acceptance and the feasibility of cET. Treatment outcome on primary assessment of OCD symptoms is assessed with Y-BOCS and secondary assessment of depressive symptoms are assessed with BDI. Work impairment is assessed with clinical interview. Paper IV provides a replication study of Paper III with the aim to investigate whether a new patient sample undergoing cET would have comparable results as those obtained in Paper III when treatment is delivered by mainly other therapists than the developers of cET. Mixed models analyses and Chi square tests are applied to compare results on Y-BOCS, patient acceptance and occupational functioning. Results: In Paper I the overall effect sizes for comparisons with waiting list (1.31) and placebo conditions (1.33) were very large. Effect sizes for comparisons between individual and group treatment were small and non-significant. CBT was better than medication (0.55), and adding medication to CBT was not more effective than CBT with placebo (0.25). Of treatment moderators, proportion of women, higher age and concurrent SSRI medication were associated with lower effect sizes. Moderators related to larger effect sizes were higher initial symptom severity, using completer analyses as opposed to intent-to-treat-analyses, using passive control (waiting list) as opposed to active control conditions, and studies assessing therapist competence. Overall mean methodological score was 23.03 (SD 4.37) in the 37 studies. The results from Paper II indicated high patient acceptance: None of the patients declined participation, no patients dropped out and the patients expressed a high degree of treatment satisfaction. All patients had marked reductions in symptoms of OCD and depression. Follow-up assessments revealed that the treatment results to a large extent were maintained three and six months after treatment. In Paper III there was high treatment acceptability. Two patients (5.4%) declined the offer of treatment and one patient (3%) dropped out prematurely. Ninety percent of the patients reported a high degree of treatment satisfaction, indicating that cET is an acceptable format. The sample had significant reductions in obsessive-compulsive symptoms after treatment, with gains maintained at the three- and six-month follow- ups. By analyzing clinically significant changes, 77% of the patients were classified as recovered six months after treatment, which is promising as the majority had long OCD duration and most patients had unsuccessfully tried previous treatment. The results in Paper IV showed that the patients had high treatment acceptance, as indicated by no patients declining treatment, no treatment dropout and high self- reported treatment satisfaction. Most patients had marked and significant reductions in symptoms of OCD, with long-term gains maintained at three and six months. By comparing the results with those obtained in Paper III, the most important finding was that equal treatment outcome was achieved by different therapists in a new sample of patients. Conclusions: The present thesis shows that CBT is an effective treatment for OCD, however, the methodological quality of the RCTs is characterized by several limitations with considerable room for improvement. Suggestions of enhanced methodological stringency in future efficacy studies are offered. Furthermore, the thesis shows that a concentrated four-day treatment format is well accepted by the patients and that the approach yields promising results. Promising results were also obtained in terms of the replicability of the format, and it was concluded that Paper IV offered a successful replication of Paper III, also when treatment was delivered by mainly different therapists.