Large confirmatory clinical trial shows efficacy and safety of new brain stimulation therapy for depression

A landmark international clinical trial led by researchers at the Centre for Addiction and Mental Health (CAMH) and University of California San Diego School of Medicine, published in The Lancet Psychiatry, has found that magnetic seizure therapy (MST) is as effective as electroconvulsive therapy (ECT)—the current gold-standard treatment for severe, treatment-resistant depression—with significantly fewer cognitive side effects. The study is the first large-scale, randomized clinical trial to directly compare MST with ECT, marking an important step toward a new treatment option for patients.

The trial, co-led by CAMH’s Dr. Daniel Blumberger and Dr. Zafiris Daskalakis at UC San Diego, was a randomized, double-blind, non-inferiority study conducted between 2018 and 2024. It enrolled nearly 300 participants across three academic centres: CAMH in Toronto, University of Texas Southwestern Medical Center in Dallas, and UC San Diego. Researchers found that nearly half (48 per cent) of patients in both treatment groups experienced a meaningful clinical response, demonstrating that MST is comparable to ECT in improving depressive symptoms. At the same time, MST showed a substantially better cognitive safety profile, particularly in preserving memory.

ECT, while highly effective, is known to cause cognitive side effects including post-treatment confusion and both short- and long-term memory loss, which remain a major barrier for patients considering the treatment.

“This is a major milestone for the field,” said Dr. Daniel Blumberger, Senior Scientist at CAMH and co-lead of the study. “For decades, we’ve known that ECT is one of the most effective treatments for severe depression, but its cognitive side effects have limited its use. Our findings show that magnetic seizure therapy can deliver similar benefits with much less impact on memory, which could make this kind of treatment a more viable option for many people who need it.”

Up to a third of people with major depressive disorder do not respond to standard treatments such as medications and psychotherapy. While ECT can be life-saving, only a small proportion of eligible patients choose to undergo it, largely due to concerns about cognitive side effects.

MST works by using magnetic stimulation to induce a therapeutic seizure, similar to ECT, but in a more targeted way that avoids areas of the brain associated with memory.

Researchers emphasize that further work is needed to support regulatory approval, training, and implementation. However, the findings lay the groundwork for MST to become a new standard option for people with severe depression, particularly those who might otherwise decline ECT.

“This study represents an important first step toward bringing MST into wider clinical use,” added Dr. Zafiris Daskalakis, Professor and Chair of the Department of Psychiatry and Dr. Igor and JoAnn Grant Endowed Chair at UC San Diego School of Medicine -. “If approved and implemented more broadly, it could transform how we deliver brain stimulation therapies and significantly improve the patient experience.”

Funding for the study was provided by the U.S. National Institute of Mental Health, with additional in-kind equipment support from MagVenture.

About the Centre for Addiction and Mental Health (CAMH) 

The Centre for Addiction and Mental Health (CAMH) is Canada's largest mental health and addiction teaching hospital and a world leading research centre in this field. CAMH combines clinical care, research, education, policy development and health promotion to help transform the lives of people affected by mental illness and addiction. CAMH is fully affiliated with the University of Toronto and is a Pan American Health Organization/World Health Organization Collaborating Centre. For more information, please visit camh.ca or follow @CAMHnews on Bluesky and LinkedIn. 

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