In Canada, 1 in 20 people live with depression. Substantial efforts have been made over the years to develop new treatments to enhance therapeutic options. One effective alternative to medication is theta burst stimulation (TBS). This technique uses magnetic fields applied to the outside of the head to modulate brain regions believed to be involved in depression. This treatment involves a daily 3-min session of stimulation (Mon to Fri) for four consecutive weeks.
Although we know TBS to be effective, we do not fully understand its detailed impact on the brain. Additionally, we know that about 50% of people respond to TBS, which is comparable to the response rate of antidepressant medication. Unfortunately, there is currently no way to predict who will likely respond to treatment. As such, doctors use a trial-and-error strategy, and need to wait several weeks before knowing if a treatment is helping a person or not.
In the proposed project, the main objective is to directly tackle these issues using an innovative brain imaging technique that allows us to simultaneously measure changes in brain metabolism and in connectivity between brain regions. Our first aim is to use this imaging technique to study the mechanisms of action of TBS on the healthy brain. Our second aim is to predict the therapeutic response to TBS treatment in people with depression, based upon changes in their brain’s metabolism/connectivity measured after their first TBS session.
This pioneering study is the first to simultaneously measure brain metabolism and connectivity to explore for predictors of outcome and mechanisms of action of TBS. Results from this study will help to directly reduce social and economic burdens for Canadians, via the development of more personalized, reliable, and efficient treatment options for people living with depression.