Title: Cognitive Behaviour Therapy for Depersonalisation-Derealisation Disorder (CBT-f-DDD): A feasibility study
Funder: Department of Health and Social Care

Abstract: Research Question Is a randomised controlled trial of Cognitive Behaviour Therapy for Depersonalisation-Derealisation Disorder (CBT-f-DDD) feasible and acceptable within routine NHS settings? Background Depersonalisation-Derealisation Disorder (DDD) is a dissociative disorder defined by distressing symptoms of unreality and detachment. Despite consistent prevalence population rates of 1-3%, the evidence base for treatment is negligible and prognosis is poor. Results from two clinical audits of CBT-f-DDD in outpatients have shown significant reductions in symptomatology and improvements in functioning, but these were uncontrolled and from a specialist clinic. Aims and Objectives This project has 4 aims: 1) to fill the demonstrable gap in effective treatments for DDD by undertaking a feasibility RCT of CBT-f-DDD to define the parameters to inform a future efficacy trial (RCT), 2) disseminate specialist CBT-f-DDD skills to generic NHS clinicians, 3) to evaluate a manualised protocol, training workshop and clinical supervision, and 4) determine whether CBT-f-DDD can be conducted within a typical NHS setting with generic CBT therapists given a brief training in DDD. Methods A CBT-f-DDD manual and workshop will be developed and around 30 generic NHS CBT therapists from inner and outer London Trusts will be trained. Eligible participants (n=60) identified within the trusts and from the UK charity for DDD (Unreal) will be randomised to receive either 6 months of CBT-f-DDD or standard care. Assessments will be conducted at four time points: eligibility, start and end of intervention, and 12-month follow-up. Mixed-method measures of feasibility and acceptability will be collated and evaluated from both participants and clinicians, to assess recruitment, eligibility and attrition rates; resources needed; health economics, power calculations; therapist adherence to CBT-f-DDD; and participant and therapist satisfaction and acceptability. Public and patient involvement is intrinsic at every stage of the study Timelines There are 3 phases of the study which will last 28 months overall. Phase 1 (4 months) will consist of participant recruitment, the development of the CBT-f-DDD manual and delivery of the workshop for clinical staff. In Phase 2 (12 months) participants will be given either 6 months of CBT-f-DDD or standard care. In Phase 3 (12 months) 12-month follow-ups will be conducted using quantitative and qualitative methods. Data analysis, write up and dissemination will be carried out. Anticipated Impact and Dissemination The proposed study is a vital step in starting to advance the treatment evidence base for this consistently under-researched, but prevalent and distressing, disorder. Data from this study will be used to refine both the treatment package and trial processes in advance of a larger efficacy trial. We hope that there will be immediate direct benefits to patients from this study with longer term benefits of providing an evidence base for treatment. There will be direct benefit to clinicians who will receive specialist training and supervision in working with DDD. There will be increased resources within the NHS as a result. Dissemination of the findings will take place within the Charity, NHS partners and UCL, through conference presentations, as well as in written peer-reviewed publications.

Lay abstract: Aims of the research Depersonalisation-Derealisation Disorder (DDD) is a distressing condition where people feel a profound sense of unreality and disconnection from the world around them. Around 1-3% of the population have DDD but there has been almost no research and there are no effective treatments. Cognitive Behaviour Therapies (CBT) are helpful in treating other mental health conditions and this study will investigate a CBT approach that has been specifically adapted for people with DDD. We have 2 aims: (1) to investigate the feasibility of using CBT-for-DDD in a small study where people with DDD are randomly divided into either having CBT or not, and (2) try this within a typical NHS setting. This will then enable us to refine the treatment and set up a large-scale clinical trial to show if it really works and how best to deliver it. Background to the research We have previously carried out two small studies which showed that CBT-for-DDD can reduce people s symptoms of DDD, and also anxiety and depression, as well as improving their work and relationships. However, in these studies we did not compare those offered CBT-for-DDD to those who weren t, so we can t be sure that it was the CBT that helped. Also, both these studies were from the same specialist clinic and so we want to know if it is possible to train general CBT therapists to deliver CBT-for-DDD so that it can be widely available in standard NHS mental health services. Design and methods used We will design a CBT-for-DDD manual and train NHS therapists in this. We will then recruit people with DDD from routine inner and outer London NHS services and a DDD charity and randomly split these people into two groups where one is given CBT and the other has standard care without CBT. After 6-months of treatment these groups will be compared to see if their symptoms have changed. We will also assess the practicalities of delivering the treatment and patients experience so we can better design a future larger study. Patient and public involvement (PPI) The UK Charity for DDD ( Unreal ) is a co-applicant on this study and will recruit people with DDD for the study via their website. Charity members will help us develop and give the clinician training and share the findings. We have set up a separate patient advisory group of 8-10 people with DDD who have already reviewed this proposal and will continue to advise at every stage of the study via bi-monthly meetings. Dissemination Professionals and people with DDD will be invited to discussion events so that we can receive feedback before submitting an application for funding of a larger trial.

Research activity codes: 6.6 PSYCHOLOGICAL AND BEHAVIOURAL
Health categories: MENTAL HEALTH