Magnetic seizure therapy, in which seizures are elicited with a high-frequency magnetic field, is under development as a new treatment for major depressive disorder. Its use may be justified if it produces the antidepressant effects of electroconvulsive therapy (ECT), coupled with limited cognitive side-effects.

To evaluate the usefulness of a new 100 Hz magnetic seizure therapy device.

We induced seizures with 100 Hz magnetic transcranial stimulation in 11 patients with major depressive disorder during one session of a regular course of ECT. Recovery times after seizures induced by magnetic seizure therapy and ECT were compared.

Seizures could be elicited in 10 of the 11 patients. Stimulation over the vertex produced tonic-clonic activity on 9 out of 11 occasions. Stimulation over the prefrontal midpoint elicited seizures on 3 out of 7 occasions. The mean duration of magnetically induced seizures was 31.3s, ranging from 10 to 86s. All patients had an exceptionally quick recovery of orientation: mean of 7 min 12s (s.d.=2 min 7 s, range 4 min 20s to 9 min 41 s). The recovery times were on average 15 min 35s shorter with magnetic seizure therapy than with ECT in the same patients (paired-samples t-test: P<0.0001). Patients reported feeling less confused after magnetic seizure therapy. Side-effects were confined to myoclonic movements, associated with the use of etomidate.

The new 100Hz magnetic stimulator elicits seizures in the majority of patients when administered over the vertex. Magnetic seizure therapy was associated with shorter recovery times and less confusion following treatment. Subsequent work will be required to assess the safety and effectiveness of magnetic seizure therapy in the treatment of depression.