Researchers test optimized brain stimulation for treatment of depression

Patient recruitment begins for Brain Canada-Bell Let’s Talk research study

Scientists at the Centre for Addiction and Mental Health (CAMH) in Toronto are set to test a novel approach to transcranial magnetic stimulation that may better organize the brain to relieve symptoms of depression, and possibly reduce the long-term risk of dementia.

The Brain Canada – Bell Let’s Talk research team, led by Dr. Tarek Rajji, is working to refine a procedure called theta-burst stimulation (TBS), which uses a different pattern of pulses than traditional non-invasive magnetic brain stimulation.

The goal is to see if a new, optimized approach to the therapy, developed by team members and basic researchers at Mount Sinai Hospital and the University of Toronto as part of the project, is better at promoting brain plasticity than the traditional approach.

The hope is, it becomes a more potent, more effective treatment for depression.

Dr. Rajji, who is also now Chair of Psychiatry at the University of Texas Southwestern Medical Center in Dallas, Texas

While repetitive transcranial magnetic stimulation (rTMS) has been an approved treatment for depressive symptoms (sadness, sleeplessness, lack of appetite and more) for more than 20 years in Canada, Dr. Rajji believes the optimized theta-burst protocol may have an added benefit. If it can help reorganize the brain’s structure and function, the treatment may be able to stave off dementia, which is twice as common in people with depression.

“One potential benefit of optimizing theta-burst stimulation, and optimizing its plasticity effect, is that maybe it could also lead to a reduction in dementia risk, especially in older people with depression,” Dr. Rajji explains.

Basic research on the project began 18 months ago when the research team was awarded the Brain Canada – Bell Let’s Talk grant “to assess, first in rodent models of depression, whether theta-burst stimulation could be optimized to generate more robust plasticity in the frontal brain region,” Dr. Rajji says.

On the foundation of the basic science experiments, led by neuroscientists Dr. Graham Collingridge and Dr. Evelyn Lambe of the Department of Physiology at the University of Toronto, “researchers are about to start the human studies and recruit 80 participants,” Dr. Rajji says.

The human-testing phase, which takes place at CAMH, will provide the optimized stimulation in a single 10-minute session in order to measure changes in the brain.

Stimulation is given via a wand that is placed over the surface of the skull to deliver short pulses of magnetic energy. The procedure isn’t painful and doesn’t require surgery.

If human testing is successful in showing more robust plasticity compared to traditional TBS, the next step is to launch a large-scale clinical trial to compare the traditional theta-burst protocol to the new one. The clinical trial would deliver more sessions and measure the symptoms of depression as well as brain plasticity.

Another important part of the research effort, led by Dr. Sanjeev Sockalingam at CAMH, is integrated knowledge translation that engages people with lived experience, learners, trainees and clinicians to inform the design of the study and the clinical treatment component.

There’s no question, brain stimulation is a promising frontier in the treatment of depression and anxiety, especially for people who choose not to take anti-depressant drugs. “When you take medication, you get side effects – liver and kidney issues, dry mouth, sexual side effects – but magnetic stimulation, including TBS, is localized on the circuits of the brain so that’s one of the main advantages of using it. It can be as effective as an anti-depressant,” Dr. Rajji says.

At the present time, brain stimulation is not covered by most provincial health insurance plans for the treatment of depression, but research advances could change that. “If there is evidence that brain stimulation is more effective, it’s more likely to be approved and covered,” he adds.