Grant: CIHR Fellowship

Obsessive thoughts and compulsive behaviours are disabling symptoms of obsessive-compulsive disorder (OCD) that can persist for decades despite traditional treatments. A promising treatment alternative for OCD is non-invasive brain stimulation. It is not well understood, however, why some patients improve with brain stimulation treatment, while others do not. The brain circuits that give rise to OCD symptoms and are modified by successful treatment might be key to understanding individual differences in treatment outcomes. In this project, we will combine single pulses of brain stimulation (transcranial magnetic stimulation) with brain activity recordings (electroencephalography) to measure the interactions between brain regions in brain circuits that have been implicated in OCD. We will collect these measurements of brain functional connectivity in 400 OCD patients and 135 healthy control participants. OCD patients will then repeat these measurements after 2 weeks of accelerated brain stimulation treatment targeting the brain circuits under study. Using this data, we aim to identify subgroups of OCD patients that show similar brain profiles. We will examine how these distinct brain profiles differ from the brain profiles of controls. We will also assess whether pre-treatment measures of functional connectivity can be used to predict which patients will benefit from accelerated brain stimulation treatment. Lastly, we will examine the changes in functional connectivity that occur when symptoms improve during treatment. From this work, we aim to discover the interactions between brain regions that perpetuate obsessions and compulsions, and how individual differences in these brain circuits translate to accelerated brain stimulation treatment outcomes in OCD. This project therefore stands to improve brain stimulation treatment for OCD, and our fundamental understanding of the brain mechanisms underlying obsessive-compulsive symptoms.