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Therapeutic seizures reduce suicidal ideation in treatment-resistant depression

A study published in Translational Psychiatry demonstrated that magnetic seizure therapy reduced suicidal ideation and produced neuroplasticity in the frontal cortex in patients with treatment-resistant depression.

“Magnetic seizure therapy (MST) is a new and promising intervention for patients with treatment-resistant depression. Compared to [electroconvulsive therapy], MST has more benign cognitive side effects due to differences in the intensity and spread of the stimulating electrical current,” Yinming Sun, PhD, from the Centre for Addiction and Mental Health, University of Toronto, and colleagues wrote. “While MST has been shown to be an effective treatment for [treatment-resistant depression], its mechanism of action has yet to be fully determined.”

In their study, the investigators assessed whether magnetic seizure therapy produced changes in suicidal ideation and neuroplasticity via transcranial magnetic stimulation and electroencephalography (TMS-EEG) of the dorsolateral prefrontal cortex.

In total, 23 patients with treatment-resistant depression received treatment with magnetic seizure therapy administered under anesthesia and neuromuscular blocker for 24 sessions or until depressive symptom remission. Using the Scale for Suicidal Ideation, researchers examined changes in suicidal ideation and the connection between TMS-EEG measures and suicidal ideation. They evaluated neuroplasticity in excitatory and inhibitory circuits using TMS-EEG measures of cortical-evoked activity and long-interval cortical inhibition from the left dorsolateral prefrontal cortex, and the left motor cortex as a control condition, prior to and following treatment.

Sun and colleagues found that mean suicidal ideation scores dropped significantly with magnetic seizure therapy and eight of 18 patients (44.4%) who had suicidal ideation at baseline experienced resolution of suicidal ideation.

After examining the dorsolateral prefrontal cortex, magnetic seizure therapy produced significant cortical-evoked activity increase over the frontal central electrodes, likely through long-term potentiation-like mechanisms, the researchers found. However, there was no change in long-interval cortical inhibition on a group level, according to the results. Moreover, change in long-interval cortical inhibition detected patients with resolved suicidal ideation with 90% sensitivity and 88% specificity.

Analysis also showed that the amount of suicidal ideation reduction after magnetic seizure therapy was linked to the decrease in long-interval cortical inhibition over the right frontal central electrodes. The investigators observed no significant finding with motor cortex assessment. Importantly, patients with simultaneous decreases in cortical inhibition demonstrated the largest drop in suicidal ideation.

“Our study suggests that MST produces neuroplasticity in the frontal cortex through [long-term potentiation]-like mechanisms,” Sun and colleagues wrote. “These findings may point to better ways of optimizing treatments for patients with [treatment-resistant depression] while improving our understanding of the biological mechanisms behind the disorder.” – by Savannah Demko

Disclosure: The authors report no relevant financial disclosures.