Towards Remission and Full Recovery From Obsessive-compulsive Disorder

Obsessive-compulsive disorder (OCD) is a disabling psychiatric illness that is characterized by distressing obsessional thoughts and time-consuming compulsive rituals. Exposure and Response Prevention (ERP) is a first-line psychological treatment of choice that requires patients to face their fears by being exposed to feared stimuli. This treatment has been shown to reduce symptoms in a significant proportion of patients. However, it is considered a difficult treatment and only a minority reach remission. Residual symptoms typically remain, or reappear after treatment, which is a risk for relapse. Inference-based Cognitive Behavioral Therapy (I-CBT) is a promising evidence-based treatment developed to overcome these limitations. I-CBT has already been found to be as effective as ERP and significantly more acceptable and easier to adhere to. There is also evidence that I-CBT is more effective for subgroups of patients. Consequently, the current research project is focused on improving treatments outcomes for those provide those who have previously unable to reach remission of their symptoms with ERP. Following an initial treatment with ERP, those that have been unable to reach remission, will be randomized to either I-CBT or more ERP. It is expected that I-CBT will be significantly more effective than providing patients with more of the same. In addition, the study aims to predict treatment outcome in order to be able to tell in advance which patients do not respond to ERP. The project is designed to maximize beneficial health outcomes with a stepped-care approach to treatment, but also to work towards a more personalized choice by being able to match patients in advance with the treatment that works best for them

Exposure and Response Prevention (ERP) improves symptoms in a significant proportion of patients, but only a minority reach remission after completing ERP (\~40%). Also, ERP is a difficult treatment that requires requires deliberate and prolonged exposure to fearful stimuli and is associated with lower levels of acceptability and tolerability. The current trial aims to overcome these limitations with Inference-Based Cognitive-Behavioral therapy (I-CBT) - a specialized form of Cognitive Behavioral Therapy that does not require provoking anxiety through exposure to fearful stimuli. To meet our objective, the current study consists of a randomized controlled trial preceded by a run-in treatment with ERP with a total of 160 patients diagnosed with OCD. Those that fail to reach remission with the run-in treatment (est. 60%) will be randomly allocated to either 18 sessions of ICBT or continued treatment with ERP. Patients will be diagnosed by standardized semi-structured interviews and treatment outcome will be assessed by gold standard clinician rated measurement of severity of symptoms by independent evaluators. For the first hypothesis, it is predicted that I-CBT is superior to continued ERP among those who have previously failed to reach remission with ERP in terms of: (a) greater improvement on our principal continuous outcome measure of OCD severity at post-treatment and follow-up; (b) clinical status at post-treatment and follow-up (treatment response, remission and relapse). For our second hypothesis, it is predicted that I-CBT is more acceptable and tolerable as compared to continued treatment with ERP for those previously unable to benefit sufficiently from ERP. For our third hypothesis, it is predicted that I-CBT is associated with more improvement on our secondary measures of outcome, including a) OC symptom dimensions and negative mood states, b) obsessive beliefs and reasoning processes, and c) psychosocial functioning. For our fourth hypothesis, it is predicted that ERP is associated with a higher frequency of combined treatment refusal and drop-out rates as compared to I-CBT. For our fifth hypothesis, tit is predicted that treatment outcome during ERP and I-CBT is associated with improvements in inferential confusion and feared-self perceptions. The secondary objective of the current proposal is to identify predictors of outcome and to use supervised machine learning to forecast which patients fail to reach remission following initial ERP treatment in order to enable the selection of patients to administer I-CBT as a first-line treatment in the future. Predictors will consist of previously identified risk factors of negative outcome, as well as proposed candidates in the extant literature

Eligibility Criteria:
Inclusion criteria:

1. a primary diagnosis of OCD according to DSM-5 criteria.
2. a score ≥ 18 on the Y-BOCS
3. age ≥ 18.
4. no change in medication during the 8 weeks before treatment for antidepressants (4 weeks for anxiolytics).
5. willingness to keep medication stable while participating in the study.
6. not undergoing a concurrent psychological treatment.
7. access to a computer or phone with internet access.

   Exclusion criteria:
8. evidence of a high level of suicidal ideation, suicidal intent or previous suicide attempts.
9. past or present psychotic or bipolar disorder.
10. neurocognitive disorder, pervasive developmental disorder or intellectual disability of a severity judged to significantly interfere with treatment and/or requiring treatment first.
11. substance abuse disorder of a severity judged to significantly interfere with treatment and/or requiring treatment first.