For years, electroconvulsive therapy (ECT) has been a lifesaving treatment for patients with treatment-resistant depression (TRD), yet exactly how it works has largely remained a mystery. Now researchers believe they have uncovered the underlying mechanisms behind its therapeutic effects — a discovery that may help clinicians better predict treatment response in individual patients and quell much of the fear and stigma associated with one of psychiatry’s most effective, yet misunderstood, treatments.
Two recent papers published in Translational Psychiatry have highlighted the significance of aperiodic neural activity. The first study showed this activity increased following ECT treatment. The second study expanded on these data by demonstrating a significant increase in aperiodic activity after patients received either ECT or magnetic seizure therapy (MST), which has a better side-effect profile than ECT but lower efficacy.
Aperiodic activity is “like the brain’s background noise, and for years scientists treated it that way and didn’t pay much attention to it,” first author Sydney E. Smith, a PhD candidate at the Voytek Lab in the Neuroscience Graduate Program at the University of California San Diego (UCSD), said in a press release.
However, aperiodic activity boosts inhibitory activity in the brain, effectively slowing it down,” the investigators noted.
In an interview with this news organization, Ms. Smith used a car analogy to explain the mechanism behind ECT. “ECT might be increasing the activity levels in the brain cells that help calm it down. It taps on the brakes that tend to malfunction in depression. By restoring the balance between the gas and the brakes in the brain, some of those depressive symptoms are alleviated,” she said.
Ms. Smith added her team’s research helps demystify one of the most effective yet stigmatized treatments for severe depression.
“Aperiodic activity as a physiologically interpretable EEG metric could be a really valuable new predictive indicator for treatment response,” she added.
Fear and Stigma
ECT is primarily used for TRD and is effective in up to 80% of patients, yet it remains one of the least prescribed treatments.
Although it’s been around for almost 90 years, fear and concern about its potential cognitive side effects have contributed to its poor uptake. It is estimated that less than 1% of patients with TRD receive ECT.
Smith noted that the 1970s movie One Flew Over the Cuckoo’s Nest still contributes to ECT’s stigma. In the film, actor Jack Nicholson’s character is forced to undergo ECT as a punishment.
It’s important for clinicians to acknowledge the stigma while advising patients that “the actual treatment doesn’t look anything like what’s in the movies,” noted Ms. Smith. Patients must give informed consent for the procedure, and it’s delivered with the lowest level of effective stimulation.
“So many steps are taken to consider comfort and efficacy for patients and to minimize how scary it can be,” she said.
ECT uses an electrical current to induce a seizure that spreads to deep subcortical structures. MST, which was developed as an alternative to ECT, uses a magnetic field to induce a more focal seizure primarily confined to the cortex.
Although MST has a better side-effect profile, experts noted it has remission rates of 30%-60% compared with ECT. Even one of MST’s inventors, Harold Sackeim, PhD, professor in the Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, is skeptical about its efficacy for TRD.
“I don’t think it works,” Dr. Sackeim, founding editor of Brain Stimulation: Basic, Translational, and Clinical Research in Neuromodulation, told this news organization.
In addition to being more expensive, MST produces a peak electrical intensity at one-tenth of what a typical ECT stimulus produces. “We’re limited by electrical engineering at this point with MST. That’s my view; others are more optimistic,” he said.