Monday, October 1, 2007

Debate heats up over suicide barrier


A recent study released by a UC Santa Barbara professor concerning the proposal to build a suicide prevention barrier on Cold Spring Arch Bridge has lit up local blogs, initiating a firestorm of debate over the effectiveness of such a barrier.
The bridge on Highway 154 has been the site of 31 suicide deaths in the past 25 years, prompting law enforcement officials, the Glendon Association and other local groups, along with Caltrans, to put in motion an effort to build a safety barrier.

Garrett Glasgow, an associate professor of political science with a background in social science statistics, states in his opening argument that there is no evidence that installing a suicide barrier at the bridge will save lives. Officials from the Glendon Association, a local nonprofit involved with suicide prevention, decried the report, saying it distorts data from previous studies.
"What the studies show is that you can stop suicide at a particular location," Glasgow said, speaking on the phone from his office at UCSB. "But you can't prevent them from going on to commit suicide with some other method."
Dr. Lisa Firestone, Glendon's director of research and education, strongly disagreed with Glasgow's conclusion and called his study a manipulation of data.
"There is a lot of good data showing that people don't substitute means," Firestone said.
One earlier study addressed both by Glasgow and Firestone in their arguments is a 1978 report by Richard Seiden — a Ph.D. and M.P.H. from UC Berkeley — that collected data on 515 people who attempted suicide on the Golden Gate Bridge in San Francisco from 1937 to 1971, but were restrained.
"After 26-plus years the vast majority of [Golden Gate Bridge] suicide attempters (about 94%) are still alive or have died from natural causes," Seiden wrote.
Glasgow said that study is frequently misinterpreted as evidence of the likely effectiveness of a suicide prevention barrier.
"Simply put, were the people in this study serious about committing suicide, or did they go to a highly visible public place and threaten to commit suicide as a 'cry for help'?" Glasgow wrote in his study. "If it is the latter, it would be a mistake to count them as examples of the lives suicide prevention barriers could save if they never intended to die in the first place."
He also argued that it is impossible to say how people would have reacted if a barrier had been built on the Golden Gate Bridge prior to their suicide attempt.
"Survivors often report they only planned to jump from a specific bridge," Glasgow wrote, "but one factor that likely influenced this preference was the fact that it was actually possible to commit suicide at this location."
Another study presented by the Glendon Association involves two bridges in Washington, D.C. A suicide barrier installed on one bridge prevented any further suicides at that location, and the number of suicides from the other bridge, nearby and in eyeshot of the first bridge, remained constant.
Glasgow said presenting that as proof of the success of the barrier is disingenuous, pointing out that the authors of that study wrote that suicide attempters frustrated in their efforts at the first bridge are not restricted only to committing suicide from the second bridge.
In response, Firestone said other potential suicide locations in the area did not see a significant rise in attempts either. She also noted the case of a bridge in New Zealand, in which a safety barrier had been removed and the suicide rate rose.
Firestone cited another study discussed by Seiden involving a significant reduction in British suicide rates following the introduction of less toxic natural gas to replace the highly lethal coke gas previously used in domestic ovens. In discussing that issue, Seiden wrote that suicide rates remained reduced for 15 years with an "almost one-to-one correspondence between the reduction of suicides and the number of persons who had used coke gas in prior years."
Firestone also discussed several other cases, such as restrictions on over-the-counter medication in England and a tax on alcohol in the Soviet Union, in which suicide rates also dipped.
"When they are in that state of being ready for action, and you put distance between them and the potential means for suicide, they are less likely to go through with it," Firestone said, adding that suicidal people are generally ambivalent and impulsive, often looking for any reason not to commit suicide.
Seiden noted in his closing paragraph that the hypothesis that suicide attempters on the Golden Gate Bridge would have found another way of killing themselves is "clearly unsupported by the data," adding "the justification for prevention and intervention such as building a suicide prevention barrier is warranted."
Data on suicide attempts from bridges is fairly limited, since it is a relatively unusual method of suicide, Glasgow said, explaining that a portion of his study attempted to approach the question of whether barriers prevent suicide from a different angle.
"If we believe the argument that suicide barriers save lives, then what we're really saying is that tall bridges are a temptation or a danger to suicidal people," Glasgow said.
To examine the relationship between the suicide rate and the number of bridges likely to attract suicidal individuals, Glasgow gathered data spanning from 1979 to 2004 on bridges nationwide. Using linear regression to graph the data, Glasgow noted that the number of bridges in a particular state increase, the suicide rate actually drops.
"There is no evidence to suggest that increased exposure to bridges increases the suicide rate," Glasgow wrote.
"We're not saying bridges cause suicides," Firestone fired back. "Having easy access to a means for suicide causes suicides."
She admitted that studying suicide is difficult, but pointed out that the evidence has been strong enough to convince the surgeon general to make restriction of means a part of the national strategy against suicide.
Glasgow said the point of his study is not to debunk earlier studies or suggest they were conducted incorrectly. Instead, he said he doesn't believe there has been enough community discussion about the effectiveness of the safety barrier.
"People are rushing forward under the assumption that it will work," Glasgow said. "...I've reviewed everything they've put forward and the answer is we don't know."
In the conclusion of his study, Glasgow said the question at hand should be whether more lives could be saved by spending the $605,000 — the estimated price tag for the bridge barrier — on other projects, pointing out that 71 people died in traffic accidents in Santa Barbara County in 2005, while only two people jumped to their deaths from Cold Spring Arch Bridge during the same year.
Firestone said the bridge has more deaths than any other spot location in the Caltrans district that includes Santa Barbara County, adding that the $605,000 price tag is less than the cost of installing a traffic light.
"We want to give a message to our community that we care and we want to prevent suicide," Firestone said. "...This is the best way to spend Caltrans money in our community."


Anonymous said...

Good work Eric, nice, balanced article.

that $605,000 will make a barrier that will last 30 years, working out to $20,000 a year.

in Santa Barbara County, $41 million a year is spent on Mental Health Services.

so for every $10,000 spent on Mental Health services, spending $5 on a Cold Spring barrier seems like a small price to pay.

It does not seem reasonable that *all* of the 515 attempted suicides that Seiden interviewed were not serious, which is Glasgow is arguing. It is far more reasonable that many were, and that does mean the Seiden study is valid.

Anonymous said...

People climb over 10' fences on SB bridges to paint graffiti. If they jump off a city bridge, it could cause others' deaths also. It is safer for the traveling public if they jump off Cold Springs, and they have an extra 15 minutes to decide their fate. - a concerned resident and witness of human body parts on train tracks, where there is no barrier.

Anonymous said...

Seiden's study seems like better evidence for the "human barriers" proposal than a $2.8 million fence.