Deep brain stimulation can durably improve depression symptoms in people who don’t respond well to other treatments, according to a small study published last week (October 4) in The American Journal of Psychiatry. The findings, based on up to eight years of data from 28 people wearing brain-stimulating implants, showed that most people receiving the therapy responded well and maintained their improvements over time, The Scientist says.

“The bottom line is that if you get better, you stay better,” study coauthor Helen Mayberg, a neurologist at the Icahn School of Medicine at Mount Sinai who holds a share of an intellectual property patent on the therapy, tells The New York Times. “You don’t lose the effects over time. You wear the device like a pacemaker, and you stay well.”

Deep brain stimulation, or DBS, involves implanting a small neurostimulator into a patient’s brain to send out electrical impulses to specific brain regions. The approach is approved by the US Food and Drug Administration to treat epilepsy and Parkinson’s disease, among other conditions, but has long been controversial in depression treatment due to mixed findings of the treatment’s effectiveness in the last couple decades.

The current study evaluated the mental health of people who had been fitted with the implants during the previous eight years. “Most patients experienced a robust and sustained antidepressant response” to the therapy, the authors write in their paper. About one-third of the participants experienced a full remission of symptoms, while half reported a reduction. The team also found no adverse health effects of the device itself, although the surgical procedure to implant it was associated with common surgical complications such as infection in some patients.

“The most impressive thing here is the sustained response,” Darin Dougherty, a psychiatrist at Massachusetts General Hospital who was not involved in the work, tells The New York Times. “You do not see that for anything in this severe depression. The fact that they had this many people doing well for that long, that’s a big deal.”

The findings support the long-term safety and efficacy of the approach for treatment-resistant depression, study coauthor Andrea Crowell of Emory University School of Medicine says in a press statement. “For people suffering from inescapable depression, the possibility that DBS can lead to significant and sustained improvement in depressive symptoms over several years will be welcome news.”