Magnetic Seizure Therapy Compared With ECT for Depression: A Large Trial

Magnetic seizure therapy (MST) is a newer convulsive treatment for depression, and earlier work suggested it has fewer cognitive side effects. The CREST-MST trial compared it with right unilateral ultra-brief electroconvulsive therapy (ECT). Both are medical treatments delivered by specialist medical teams, not by psychologists.

The randomised, double-blind trial ran at three academic centres across Canada and the USA. Adults with major depressive disorder were treated until they achieved remission, dropped out, or reached up to 21 treatments. The two main outcomes were remission of depression and worsening of autobiographical memory.

Remission rates were 27.8% with ECT and 22.5% with MST, a difference of 5.3% in favour of ECT. That was within the study's margin, so MST was judged non-inferior. Worsening autobiographical memory affected 17.3% of the ECT group and 2.7% of the MST group. Twelve ECT participants and three MST participants withdrew because of non-serious adverse events. Enrolment concluded before reaching the intended sample size.

The authors conclude that MST showed non-inferior efficacy and a more favourable cognitive safety profile, and that it deserves consideration as a first-line convulsive therapy, particularly for people who refuse ECT. The memory finding was large. The remission difference was small.

If depression is not lifting, talk with your GP or psychologist about the full range of options, including referral to a specialist team.

What the study did

Magnetic seizure therapy (MST) is an innovative convulsive therapy that is clinically beneficial for patients with depression and has fewer cognitive adverse effects. The CREST-MST trial aimed to confirm its efficacy, tolerability and cognitive safety against right unilateral ultra-brief pulse-width (RUL-UB) electroconvulsive therapy (ECT). Both treatments are delivered in a medical setting by specialist medical teams, rather than within psychological practice.

It was a multisite, randomised, double-blind, parallel-group, non-inferiority trial at three academic centres across Canada and the USA. Participants aged 18 years and older with major depressive disorder were treated until remission, dropout, or up to 21 total treatments. MST was delivered using a twin coil in a midline frontal position.

The co-primary outcomes were remission of depression on the Hamilton Rating Scale for Depression-24 item and worsening of autobiographical memory on the Autobiographical Memory Test. The non-inferiority margin was a 15% absolute difference in remission rates, and memory worsening was defined as a 25% reduction. People with lived experience were not directly involved, although the study was informed by indirect feedback from previous trials and clinical discussions with people with depression who declined ECT.

What it found

Between June 26, 2018 and March 1, 2024, 292 participants were enrolled, 239 were randomly assigned, and three withdrew before treatment. Remission was 27.8% with RUL-UB ECT and 22.5% with MST, a 5.3% difference in favour of ECT. This established non-inferiority of MST (Z-test p=0.048, 95% CI -4.4 to 14.9).

More ECT participants had worsening autobiographical memory (17.3%) than MST participants (2.7%; p=0.0003). Twelve participants in the ECT group and three in the MST group withdrew from treatment due to non-serious adverse events.

Why it matters

Memory effects are one of the main reasons some people decline ECT. The authors interpret the results as showing that MST achieved remission at a non-inferior rate with a more favourable cognitive safety profile, and they say its overall risk-benefit profile supports consideration as a first-line convulsive therapy in major depression, particularly for people who refuse RUL-UB ECT.

Limits

Enrolment concluded before reaching the intended sample size. Remission rates were lower than many people might expect for either treatment, and ECT showed the higher figure numerically. The non-inferiority conclusion rests on a margin set in advance, and the confidence interval is wide. The abstract also notes that people with lived experience were not directly involved in the study's design.

Reading the results in context

A non-inferiority trial asks a particular question. It does not ask whether a new treatment is better. It asks whether the new treatment is not worse than the standard by more than a set margin. Here the margin was a 15% absolute difference in remission rates, and the observed difference of 5.3% in favour of ECT fell within it.

The two co-primary outcomes pulled in different directions, and both belong in the picture. ECT showed the higher remission figure numerically, while MST showed less worsening of autobiographical memory. The authors weigh these together in their interpretation, concluding that the overall risk-benefit profile of MST supports its consideration as a first-line convulsive therapy in major depressive disorder.

Participants who withdrew from treatment due to non-serious adverse events also differed between the groups, with 12 in the ECT group and three in the MST group. The trial was funded by the National Institutes of Mental Health.

Seeking help

Decisions about convulsive therapies belong with a psychiatrist and the treating team, alongside your GP and psychologist. If depression has not responded to other treatment, please raise the question with them, and do not hesitate to seek support if you are struggling.