Condition category
Mental and Behavioural Disorders
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status

Plain English Summary

Not provided at time of registration

Trial website

Contact information



Primary contact

Dr Clara Strauss


Contact details

Psychology Department
United Kingdom

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

A comparison to two types of group behaviour therapy for obsessive compulsive disorder: A pilot randomised controlled trial of behaviour therapy and mindfulness-based behaviour therapy for OCD


Mindfulness-based behaviour therapy for OCD: a pilot RCT

Study hypothesis

Obsessive compulsive disorder (OCD) affects up to one million adults in the UK (NICE, 2005). People diagnosed with OCD experience unwanted obsessive thoughts and engage in compulsive behaviours. Exposure and response prevention (ERP) is a behaviour therapy and it is the psychological therapy with the strongest evidence for effectiveness. However, only 60% of people benefit from ERP. Many people do not find ERP acceptable, with about 25% of people starting ERP dropping out.

Mindfulness-based interventions (MBIs) teach people to notice unpleasant thoughts and feelings without reacting unhelpfully. Although effective for depression, psychosis and a range of anxiety disorders, there is very little research on the effectiveness of MBIs for OCD, although the research that is published shows promise.

We conducted a focus group with six people diagnosed with OCD and who had experience of ERP and MBI. We had intended to compare MBI to ERP, however participants advised us to combine ERP with MBI. They suggested that effectiveness might be based by combining the two together. We have followed their advice in this study.

We intend to compare ‘standard ERP group behaviour therapy’ (BT) to ‘mindfulness-based ERP group behaviour therapy’ (MBBT) to see if mindfulness practice improves ERP outcomes and reduces drop-out. Before we can answer this question in a fully-sized trial we first need to conduct a pilot study. This pilot study is a small version of the fully-sized trial. It will tell us: (a) the approximate difference in outcome between BT and MBBT, (b) how easily we can recruit to the study, and (c) how many people drop out. This information will allow us to know how many participants we need for the full trial, how long recruitment will take and how to reduce drop-out rates. Once we have this information we will apply for funding for the full trial.

Ethics approval


Study design

Randomised; Interventional; Design type: Treatment

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet


Topic: Mental Health Research Network; Subtopic: Personality disorder; Disease: Personality disorders


Behaviour Therapy: A 10 session exposure and response prevention for OCD group intervention (maximum 10 participants per group). Each session will run for two hours.
Mindfulness Behaviour Therapy: A 10 session mindfulness-enhanced exposure and response prevention for OCD group intervention (maximum 10 participants per group). Each session will run for two hours. Mindfulness practice and discussion will be added to the standard ERP protocol.
Follow Up Length: 6 month(s); Study Entry : Registration only

Intervention type



Drug names

Primary outcome measure

Yale-Brown Obsessive Compulsive Scale - Second Edition (Y-BOCS-II; Goodman et al, 2006).; Timepoint(s): Baseline, post-therapy (10 weeks post-baseline) and 6-months post-therapy

Secondary outcome measures

1. Beck Depression Inventory - second edition (BDI-II; Beck et al, 1996)
2. Change Interview (Elliott et al, 2001).; Timepoint(s): Post-therapy only
3. Five-Facet Mindfulness Questionnaire - Short Form (FFMQ-SF; Bohlmeijer et al, 2011)
4. Mini Neuropsychiatric Interview 6.0.0; Timepoint(s): Baseline, post-intervention and six months post-therapy
5. Obsessional Beliefs Questionnaire - Revised - OBQ-44; Timepoint(s): Baseline, post-therapy and six months post-therapy
6. Short Warwick-Edinburgh Mental Well-Being Scale (2007); Timepoint(s): Baseline, post-therapy and 6-months post-therapy
7. Therapy attrition; Timepoint(s): Percentage of participants who complete their intervention will be recorded as a primary outcome

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Meet diagnostic criteria for OCD (MINI 6.0.0 interview)
2. Have been stable on psychiatric medication for at least three months prior to the consent meeting, or not taking psychiatric medication for at least three months prior to the consent meeting
3. Have no plans for changes to psychiatric medication during the course of the study
4. Have not received psychological therapy in the past three months or to have any plans for psychological therapy during the course of the study
5. Be aged over 18 years of age

Participant type


Age group




Target number of participants

Planned Sample Size: 40; UK Sample Size: 40

Participant exclusion criteria

Exclusion criteria will be that participants will not have an identified organic cause for their OCD symptoms or a diagnosed learning disability. This will be ascertained through the care team. People will be excluded if they meet diagnostic criteria, based on the MINI interview, for; post-traumatic stress disorder, anorexia nervosa, an autistic spectrum disorder or a psychotic disorder.

To reflect the reality of mental health services and the co-morbidity of OCD with other anxiety disorders and with depressive disorders (NICE, 2005), co-morbidity with these conditions will not be an exclusion criterion. The exception to this is that people meeting diagnostic criteria for PTSD will be excluded given some concerns in the MBI literature about the offering MBIs to this population. People presenting with hoarding only compulsions will be excluded from the study, given the recent move to classify hoarding as a distinct condition from OCD (Pertusa et al, 2008).

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

University of Surrey
United Kingdom

Sponsor information


Sussex Partnership NHS Foundation Trust (UK)

Sponsor details

Sussex Education Centre
Nevill View Hospital
United Kingdom

Sponsor type

Hospital/treatment centre



Funder type


Funder name

National Institute for Health Research: Research for Patient Benefit (RfPB)

Alternative name(s)


Funding Body Type

government organisation

Funding Body Subtype

National government


United Kingdom

Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Basic results (scientific)

Publication list

2015 protocol in:
2018 results in:

Publication citations

Additional files

Editorial Notes

11/01/2019: Publication reference added.