People with severe depression who receive electroshock therapy are significantly less likely to commit suicide, a new evidence review says.

Electroconvulsive therapy (ECT) lowered the risk of death by suicide 34% among patients with severe depression, according to findings published June 13 in the journal Neuroscience Applied.

Depression patients receiving ECT also had a 30% lower risk of death from any cause, researchers said.

They said these benefits might be even greater than reflected, given that ECT has improved as a psychiatric treatment.

“Modern ECT appears to be more effective than it was in the past,” said lead researcher Dr. Timur Liwinski, a clinician scientist at the University of Basel in Switzerland.

“Since our analysis spans many decades, it’s likely that today's ECT offers even stronger protection against suicide than the 34% reduction we identified overall,” Liwinski said in a news release.

Major depression affects an estimated 300 million people worldwide, with the number increasing about 20% between 2005 and 2015, researchers said in background notes.

Each year nearly 700,000 die by suicide, and about half of these deaths are linked to depression or related mood disorders.

Overall, people with mood disorders have a 20-fold higher risk of suicide, researchers said.

During ECT, small electrical current pulses are sent through the brain to trigger seizures, researchers said. This essentially reboots the brain, altering levels of brain chemicals and potentially enhancing the brain’s adaptability.

ECT is performed under anesthesia and is most often used in serious mental illnesses like major depression and bipolar disorder, according to the National Alliance on Mental Illness (NAMI).

The treatment is underused, however, due to stigma surrounding it, NAMI noted. Movies like “One Flew Over the Cockoo’s Nest” and “Frances” portray electroshock therapy as barbaric and harmful.

For this paper, researchers pooled data on 11 previous studies comparing nearly 18,000 people treated with ECT to more than 25,300 who were receiving standard care for depression.

There were 208 suicide deaths and 511 deaths from any cause among the ECT patients, compared to 988 suicide deaths and 1,325 overall deaths among patients receiving usual depression treatment, results show.

Newer studies tended to report greater benefits from ECT than older ones, indicating that the therapy is being applied more effectively as time passes, Liwinski said.

Because the studies were observational and not clinical trials, they cannot draw a direct cause-and-effect link between ECT and lowered suicide risk, he added.

“However, because people with severe depression and suicidal thoughts are such a vulnerable group, it is unlikely that long-term, high-quality experimental studies will be possible in the future,” Liwinski said.

Martin Balslev Jørgensen, a professor of psychiatry at the University of Copenhagen who reviewed the findings, called the new study “valuable” and “important.”

“Although the effect of ECT on suicidality is well known among clinicians, it is helpful to have it so clearly documented,” he said.

If you or a loved one are experiencing a suicidal crisis or emotional distress call the Suicide and Crisis Lifeline at 988.