Among patients receiving electroconvulsive therapy (ECT) for major depression, those who experienced longer therapeutic seizures had higher odds of depression remission, according to a study in JAMA Network Open.

Compared with patients whose seizure duration during their first ECT treatment was less than 20 seconds, those who had seizures lasting 30 seconds or more were more than twice as likely to remit by the end of treatment; seizure durations of around a minute seemed to offer the highest odds of remission.

Cecilia Gillving, M.B., of Örebro University in Örebro, Sweden, and colleagues used data from a Swedish ECT registry to examine outcomes of all patients who received unilateral ECT (placing both electrodes on the same side of the head) for major depressive disorder between 2012 and 2019. At each ECT session, the duration of the therapeutic seizure was monitored with electroencephalography (EEG), although the study involved only the patients’ first session.

The study sample included 6,998 individuals (60.4% female) with an average age of 55. Of this group, 39.3% achieved remission of their depression symptoms, usually after six to nine sessions. Patients whose first seizure was less than 20 seconds had the lowest remission rate at 27.2%. The odds of remission then increased for every 10 extra seconds of seizure duration, peaking at 60 to 69 seconds, which was associated with 2.52 times the odds of remission. (Seizure durations of 70 seconds or more were associated with 2.45 times the odds of remission compared with seizures of less than 20 seconds.)

Gillving and colleagues also found that patients who were taking anticonvulsants such as lamotrigine or benzodiazepines had shorter seizure durations on average compared with patients not on these medications, and also had a correspondingly reduced rate of remission.

In an accompanying editorial, James Luccarelli, M.D., D.Phil., of Harvard Medical School, cautioned about extrapolating the findings too broadly. “[E]ven among those with initial seizures of less than 20 seconds the remission rate from depression was 27.2%, which is much greater than that obtained by pharmacotherapy in patients with treatment resistance,” Luccarelli wrote. “As a result, a short seizure at the time of first treatment should not be a reason to discontinue ECT in patients for whom treatment is indicated.”

For related information, see the Psychiatric News article “ECT for Depression May Cut Suicide Risk by Nearly 50%.”

Photo: (credit to University of Michigan)