Deep brain stimulation can help many patients with tough-to-treat depression, says a Canadian study. In deep brain stimulation, electrical impulses are delivered through electrodes implanted in the brain.

The patients in the study had major depressive disorder, a severe form of depression that's unresponsive to other treatments. One month after the start of deep brain stimulation, 35 percent of patients responded well to the therapy, with 10 percent of them entering remission, CBC News reported. Six months after the start of treatment, 60 percent of patients showed a good response and 35 percent were in remission.

"Our research confirmed that 60 percent of patients have shown a clinically significant response to the surgery and the benefits were sustained for at least one year," Dr. Andres Lazano, a neurosurgeon at the Krembil Neurosciences Centre at Toronto Western Hospital, said in a news release.

Lozano and colleagues said there were few serious side effects and no patients suffered long-term harm from the surgery to implant the electrodes, CBC News reported.

The study was published in the journal Biological Psychiatry.