Title: FEasibility and Acceptability Of Transcranial Stimulation in Obsessive Compulsive Symptoms (FEATSOCS).
Funder: Department of Health and Social Care

Abstract: Background: Obsessive-compulsive disorder (OCD) is a common, costly and disabling compulsive disorder. Existing treatments are only partially effective. Changes in cortico-striatal neural connectivity and cognitive processing are relatively well-defined and represent core pathoplastic features. Transcranial direct current stimulation (tDCS), a non-invasive technique for modulating intracerebral neuronal activity that is relatively straightforward to administer, has considerable potential for clinical application as a safe and cost-effective treatment. Proof of principle studies suggest tDCS is efficacious and well tolerated in OCD when applied to the supplementary motor area (SMA) and orbitofrontal cortex (OFC) - accessible nodes in the cortico-striatal circuits implicated in a broad range of compulsive disorders. The existing studies are however small and inconclusive, and indicate the need for a RCT. Mechanistic studies suggest that tDCS of the SMA or OFC may favourably alter connections in cortico-striatal circuits and enhance aspects of cognition in domains of relevance to OCD (inhibition, habit, cooperativeness, flexibility). There are thus grounds to believe that modulation of these neural pathways with tDCS would improve OCD symptoms and may be used to augment the treatment-response to optimise clinical outcomes. Aims: As the existing data is inadequate to support a fullscale trial, FEATSOCS addresses key research questions and knowledge gaps to enable the design of the most efficient, cost effective study. We propose a double-blind, sham-controlled, crossover feasibility study of multi-session tDCS of the SMA and OFC. We apply neurocognitive tests to search for preliminary evidence supporting the hypothesis that tDCS of the SMA and OFC act by altering neurocognitive mechanisms of relevance to OCD, and to identify potential mechanisms as targets for treatment development. Progression to a full trial will be pursued if specific criteria related to acceptability, tolerability, feasibility of recruitment and efficacy are met. Research questions: A. The use of tDCS in research and practice &bull; Acceptability, tolerability and safety of the intervention &bull; Feasibility of recruitment &bull; Adherence to tDCS and study assessments &bull; Willingness of clinicians to recruit participants &bull; Practicality of applying tDCS in the clinical setting B. The effect of tDCS in OCD; &bull; Optimal stimulation target (OFC, SMA) &bull; Likely magnitude of effect of the intervention on OCD symptoms, to determine standard deviation of the outcome measure, to estimate sample size &bull; Duration of effect of a course of stimulation, to space treatments efficiently &bull; Usefulness and limitations of specific neurocognitive tests to determine a definitive test battery Research Plan: We investigate the effect of multiple sessions (four twice-daily applications) of tDCS in 25 adult volunteers with OCD. We will collect information about recruitment, study conduct, tDCS delivery, and assessment methods to inform future trial design. The study will compare the effect of active and sham interventions on the challenge version of the Yale Brown Obsessive Compulsive Scale (Y-BOCS) (10). We will focus on the ratings performed 24 hours after stimulation as a potential primary outcome measure in the future definitive study. We will evaluate underlying mechanisms using cognitive tests with established neural correlates. We will disseminate the results via robust health and neuroscience networks. Benefit to patients and the NHS: FEATSOCS evaluates the potential for non-invasive neuromodulation to optimise clinical outcomes in OCD and shed light on the clinical and brainbased factors mediating the response. If feasibility is established, progression to a full multi-session trial will be pursued, to investigate the use of tDCS alone in early phase OCD, and potentially as an adjunct to cognitive behaviour therapy (CBT) for treatment-resistant patients. Thus, by advancing NHS research, FEATSOCS would impact positively on NHS services and the health and wellbeing of patients, families and the wider community.

Lay abstract: Aim This project tests whether small electrical currents applied to the scalp can help treat obsessive compulsive disorder (OCD). Some current passes into the brain where it may change brain functioning. Evidence suggests this could help ease OCD symptoms. This type of brain stimulation is new and experimental, so this project aims to answer basic questions, including if it shows signs of working, what are the side effects and if doctors and patients are willing to use it. The project also looks at which areas of the brain should be targeted and how long the effects last. This information would help design and implement larger clinical trials. Background OCD is a disabling, enduring illness affecting 2-3% of people. OCD profoundly affects lifestyle, placing a severe burden on the person, their family and health services. About 40% of people with OCD are not helped by available treatments. New approaches are needed. One promising new treatment involves passing a small, almost imperceptible electric current into brain areas connected to OCD. This may help people with OCD think and behave differently and could help treatments work better. Patient and public involvement Patients helped design the study. They will also help communicate its findings. Design Patients with OCD visit a clinic for six days over a 3 month period. On some visits they have a region of brain stimulated twice with very small amounts of electric current, on others they are told they are having the stimulation but the current is turned off. This helps scientists test whether the stimulation has an effect. Symptoms and wellbeing are assessed before and after stimulation (or mock-stimulation) using simple tests to track changes in thinking patterns. Dissemination Findings are communicated through publication in scientific journals, talks at science meetings, discussions among patient support networks and the media.

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