A new analysis suggests that several different types of interventions could help reduce the risk of suicide at these hot spots, typically bridges, cliffs or other high places.
Jane Pirkis, a professor at Australia's University of Melbourne in the Melbourne School of Population and Global Health
, and colleagues in Australia and Hong Kong looked at studies on the number of suicides before and after interventions were in place in 18 different hot spots in the United States, Canada, Australia, New Zealand, China and Europe.
The researchers found that installing barriers at bridges and railway platforms was associated with a reduction in suicide risk of 93%, and providing signs with help line numbers at these sites could reduce the risk by 61%.
However, interventions at suicide hot spots will not have a big impact on the overall suicide rate because they are only involved in a small percentage of suicides overall, Caine said. Of the approximately 40,000 people who take their own lives every year in the United States, most use guns (52%), hanging (25%) or poisoning (16%), and only a small number jump from a tall height (2%) or in front of a moving object (1%).
Although it is important to put interventions in place at common suicide locations, "we have got to have a strategy where fewer people come to suicide attempts, (because) once someone is determined to die, it is much harder to intervene," Cain said. This strategy should be multifaceted and include improving mental health services and helping people who are abused, he added.
The authors of the Lancet article urged interventions at suicide hot spots, "not only to prevent so-called copycat events, but also because of the effect that suicides at these sites have on people who work at them, live near them, or frequent them for other reasons."
The current analysis suggests that three types of strategies can have big effects: reducing access to the sites, providing information about getting help and making it easier for another person to intervene.
One of the most studied interventions for reducing deaths at suicide hot spots involves reducing access. It was associated with between 62% and 99% fewer suicide deaths in 10 different studies.
One of the studies found that Beachy Head, one of the highest sea cliffs in the United Kingdom, had about 16 suicides a year in the 1980s and 1990s. But in the months after road access was blocked in 2001 -- because of concern over an outbreak of foot-and-mouth disease
in animals -- the number dropped to zero. At the Jacques Cartier Bridge in Montreal, annual suicides decreased from 10 to 2.6 after the construction of a tall fence.
It is not surprising that these physical barriers help reduce suicide deaths, said Steven Vannoy, associate professor of counseling and school psychology at University of Massachusetts Boston. "If people encounter something that slows them down, that makes them have to be conscious of what they're doing, that may psychologically cause them to not do it," he said. People want to think the suicide will be easy and effective, he added.
Other suicide hot spots where barriers were linked with fewer suicides were:
• Ellington Bridge in Washington
• Memorial Bridge in Augusta, Maine
• Bloor Street Viaduct in Toronto
• Clifton Suspension Bridge in Bristol, England
• Canton Hospital in Baden, Switzerland
• Muenster Terrace in Bern, Switzerland
• Gateway Bridge in Brisbane, Australia
• Gap Park in Sydney
• Grafton Bridge in Auckland, New Zealand
• Lawyers Head cliff in Dunedin, New Zealand
• The underground railway system in Hong Kong
The Golden Gate Bridge does not currently have any barriers in place, although a plan has been approved to build a steel net 20 feet below where people jump. "There is a good reason to believe it would reduce the number of suicides," Vannoy said.
Several studies have looked at the impact of encouraging people to get help, such as installing signs with numbers for suicide hotlines and crisis telephones in the hotspot area.
At the Mid-Hudson Bridge in upstate New York, there were five suicides per year on average in the years before signs and crisis phones were installed, compared with 2.3 suicides after.
Signs providing numbers for help had similar effects at a car park in southern England where people would go to poison themselves on car exhaust.
However, crisis telephones had the opposite effect on the Skyway Bridge in St. Petersburg, Florida, where 3.7 people per year took their own lives before phones were installed in 1999, compared with 8.2 people after. The authors of the analysis suggest this increase could have been due to a website that promoted suicides using the bridge, which became popular around the same time the phones were added.
Patrolling the area
Some sites have stationed police officers on bridges and cliffs to help intervene in suicide attempts. But studies have only looked at the effects of these efforts in combination with installing fences or crisis phones and not on their own.
In a study in Cheung Chau, an island off Hong Kong, programs that included police patrols as well as phone hotlines were found to reduce the number of suicides from about 8.7 to 1.7 per year. The area is considered a suicide hot spot because people rent holiday apartments where they poison themselves with carbon monoxide.
Having a person intervene could probably be very effective, but somebody would have to be present at all times, Vannoy said. "Just having a witness there can slow somebody down and make them think about what they're doing," he said, adding that most people who want to attempt suicide do not want others to see them.
Having someone patrol a suicide hot spot could be a much less expensive strategy, and possibly more cost-effective, than projects like the steel net below the Golden Gate Bridge, Vannoy said.