Grant: Operating Grant

Obsessive-compulsive disorder (OCD) is a severe and debilitating anxiety disorder afflicting about 2% of the population. It is characterized by the presence of recurrent obsessions and/or compulsions that are time consuming and cause marked distress and/or impairment. Untreated, OCD runs a chronic and deteriorating course. According to the World Health Organization, OCD is among the top 10 leading causes of disability worldwide. Examination of non-medicinal treatments for OCD has focused on cognitive-behavioural treatment (CBT). CBT is considered first line psychological treatment for OCD. However, there are still a substantial amount of treatment non-responders and the majority of responders are left with residual symptoms. One area of investigation that has shown potential benefit for general mood and anxiety disorders has been regular aerobic exercise, yet the potential benefits of exercise in OCD have not been widely tested. The purpose of this study is to examine the benefits of a standardized 12-week aerobic exercise program as a stand-alone treatment and when added to a standard 12-week CBT protocol in the treatment of OCD. A second major aim is to determine whether exercise alone or combined with CBT can reduce the cognitive dysfunction associated with OCD. We will also examine whether certain genes related to OCD, learning and cognitive change, relate to the extent to which participants improve in exercise, CBT and their combination. Treatment outcomes will be assessed in relation to symptom and cognitive measures of clinical improvement. If this study can demonstrate that a short aerobic exercise program can confer additional clinical gains for those suffering with OCD, then it could easily be translated into routine clinical care. Results can potentially add to our understanding of the treatment mechanisms behind OCD and improve our understanding of the clinical picture of those afflicted, as well as provide us with more efficacious treatment options.