September 22, 2015 7:01 PM EDT

Suicide has no simple cause and no single cure. But there’s new evidence that simply blocking off popular routes to suicide, like erecting a fence around a cliff’s edge, can cut down on suicide deaths enormously.

A new meta-analysis, published in the Lancet Psychiatry journal, looked specifically at what the authors call “suicide hotspots”: sites accessible to the public and often used as a means to suicide, like bridges, cliffs, tall buildings and railroad tracks. Suicide attempts at these spots are likely to be fatal, and because of how the spots are sometimes used, they tend to gain a reputation. “There’s something unique about these sites, and because of their self-perpetuating nature, they can have an impact on so many people,” says lead author Jane Pirkis, a professor at the University of Melbourne in Australia. “It’s definitely worth doing something at those sites.”

Pirkis and her team analyzed 18 studies that looked at three interventions to deter suicides at hotspots. Of those studies, 13 looked at restricting access to means: putting up barriers and structural interventions around the site. Other studies evaluated the effectiveness of encouraging suicidal people to seek help, by putting up signs or phone lines for suicide crisis services, or putting cameras or trained staff in hotspots to increase the likelihood that a third party would intervene before a suicide happened.

“The bottom line is all of those interventions seem to work quite well”—either alone or together, Pirkis says. Both help-seeking and third-party intervention reduced suicides at the sites by at least 50%.

But the most effective strategy was to physically restrict access to suicidal hotspots. Doing so yielded a 90% reduction in suicides at the sites.

It may seem like a fence or a barrier would be too small of a gesture to stop a suicide, or that people who are suicidal will simply find another spot to take their lives. That’s a fallacy, says Pirkis, since suicides are often more impulsive and less premeditated than we think. “You can take the opportunity to change the track of a person’s thinking,” she says, just by setting up a small barrier.

One of the studies the team analyzed was conducted on a road in New Zealand that lead to a famous cliff sometimes used for suicides. A barrier had been erected there, not for suicide prevention but for road work. Even though the barrier was flimsy, suicides at that site dropped from 13 before the barrier was erected to zero. “In about a third of the studies we pooled, there’s a reduction to zero,” Pirkis says. “I think that’s pretty compelling evidence.”

Financial and aesthetic concerns mean putting up a barrier at a suicide hotspot isn’t always practical. But the good news is that the other two interventions—posting information on suicide crisis services and working to involving third parties—are also effective while being comparatively easier to introduce, according to the evidence. “We’re able to say with a bit more certainty that these are really good interventions,” she says.

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Write to Mandy Oaklander at mandy.oaklander@time.com.

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