Clinical pilot study of inference based psychological therapy for body dysmorphic disorder

INTERVENTION: Randomization. Following diagnosis and baseline assessment, participants who meet eligibility criteria will be randomly allocated to one of two treatment modalities at point of entry into the study using a computerized random number generator with a randomization ratio of 1:1, performed by an independent statistician. Allocation Concealment Mechanism: The allocation sequence will be concealed from the evaluators. Modality 1. Cognitive behavioral therapy (CBT) will be based on a standard, commonly‐used manual for BDD that contains standardized forms for exercises and homework assignments. Core treatment components include: a) psychoeducation, b) motivational enhancement strategies, c) cognitive restructuring that addresses negative thoughts and maladaptive beliefs about appearance (e.g. the importance of appearance or self‐worth), d) exposure and response prevention to avoided situations as guided by a hierarchy, e) mindfulness interventions and perceptual retraining (e.g., observing one’s body without selective attention to details and flaws and approach oneself in a non‐judgemental manner) and f) relapse prevention focused on the consolidation and maintenance of gains. Beyond these core elements, the treatment program also includes several optional modules therapists can utilize to tailor the treatment to symptoms that occur in some, but not all BDD patients, including: a) skin picking and hair pulling, b) weight, shape and muscularity, c) cosmetic treatment and d) depression. To conform with previous studies and guidelines, specific criteria will be applied to guide the use of these optional modules, based on scores on the BDD‐Symptom Scale (BDD‐SS); 2) level of depression as assessed by the BDI, 3) participant preferences and 4) clinician judgement. For all patients, treatment ends with relapse prevention strategies and booster sessions focused on helping patients maintain their gai CONDITION: Body dysmorphic disorder ; Mental and Behavioural Disorders ; Body dysmorphic disorder PRIMARY OUTCOME: BDD symptoms assessed using the Yale‐Brown Obsessive‐Compulsive Scale Modified for BDD (BDD‐YBOCS) at pre and post‐treatment INCLUSION CRITERIA: 1. Age > 18 years 2. A primary diagnosis of BDD according to DSM‐5 criteria 3. No change in medication during the 12 weeks before treatment for antidepressants (4 weeks for anxiolytics) 4. Willingness to keep medication stable while participating in the study (g) not undergoing a current psychological treatment 5. Willingness to undergo active psychological treatment 6. Willingness to undergo randomization into treatment modality 7. Fluency in French SECONDARY OUTCOME: ; 1. BDD symptoms assessed pre and post‐treatment by self‐report with the Body Dysmorphic Symptom Scale (BDD‐SS); 2. Overvalued ideation ‐ Level of OVI will be assessed pre and post‐treatment with the Over‐Valued Ideas Scale (OVIS); 3. Anxiety will be assessed pre and post‐treatment with The Beck Anxiety Inventory (BAI); 4. Depression will be assessed pre and post‐treatment with the Beck Depression Inventory (BDI); 5. Obsessive beliefs will be measured at pre‐ and post‐treatment with the 20‐item version of the Obsessive Beliefs Questionnaire (OBQ‐TRIP); 6. Level of inferential confusion will be formally assessed at pre‐treatment, post‐treatment and follow‐up by the validated Inferential Confusion Questionnaire — Expanded Version (ICQ‐EV); 7. Feared self‐perceptions will be assessed pre‐ and post‐treatment with the expanded version of the Fear of Self Questionnaire (FSQ‐Expanded Version).; 8. Dissociative Absorption will be assessed pre and post‐treatment with an adapted version of the Selves Questionnaire; 9. Obsessive‐compulsive symptoms will be assessed pre and post‐treatment with the Vancouver Obsessive‐Compulsive Inventory (VOCI); 10. Dissociation will be assessed pre and post‐treatment with the Dissociative Processes Scale (DPS); 11. Disability and impairment in work, social life and family responsibilities will be measured pre and post‐treatment with the Sheehan Disability Scale (SDS); 12. Quality of life will be assessed pre and post‐treatment with the Brunsviken Brief Quality of Life Scale; 13. Social self‐esteem will be assessed pre and post‐treatment with the Social Self‐Esteem Inventory (STI); 14. Global self‐esteem will be assessed pre and post‐treatment with the Rosenberg’s Self‐Esteem Scale (RSES); 15. Self‐report measures to measure treatment acceptability and satisfaction will be administered immediately following the 1st, 8th and 16th treatment session:; 15.1 Distress/Endorsement Validation Scale (DEVS); 15.2 The Treatment Acceptability/Adherence Scale (TAAS); 15.3 The Credibility and Expectancy Questionnaire (CEQ); 15.4 Evaluation of Treatment Questionnaire (ETQ); These questionnaires will be provided to patients in a sealed envelope and returned by mail to the project manager to minimize potential bias. In addition, we will ask each patient that refuses or drops out of treatment to list the reasons they refused or discontinued treatment utilizing an inventory with a list of potential reasons developed by Hansen, Hoogduin, Schaap & De Haan (1992);