In what is said to be the largest study of its kind, Toronto researchers found the risk of suicide following an initial attempt — in this case, non-fatal self-poisoning — was 42 times higher than that of the general population.
Researchers tracked every person who visited a hospital emergency department in Ontario for self-poisoning between April 2002 and December 2010. They identified 65,784 children and adults who survived the suicide attempt, including almost 18,500 teenagers.
Of the 65,000-plus patients discharged after a self-poisoning episode — the most common way of trying to take one's own life — 4,176 individuals died during the followup study period, 976 of them by suicide.
Among those who died by suicide were 107 teens, who ended their own lives just over two years on average after their first attempt.
"I think the key message is that patients at all ages — both teenagers and adults — who present to hospital with a first episode of intentional self-poisoning are at a significantly increased risk of suicide over the ensuing decade," said Dr. Yaron Finkelstein, lead author of the study published Wednesday in the journal JAMA Psychiatry.
Self-poisoning is often the result of overdosing on over-the-counter or prescription drugs or ingesting a noxious substance.
While some are treated and discharged from the ER, more severe cases are admitted for critical care or for psychiatric care if they appear unstable and likely to imminently harm themselves again.
"About 99 per cent of those who reach hospital alive are surviving," said Finkelstein, an emergency room physician at the Hospital for Sick Children. "And that is the opportunity to identify them and implement prevention for subsequent attempts.
"Most individuals who eventually died by suicide used more violent methods on subsequent attempts, and only seven per cent of them reached hospital alive."
The average time to suicide following a first attempt was 18 months, the research found, and about a quarter took their own lives more than four years later.
"The suicide risk is durable over many years after the first presentation," said Finkelstein. "And therefore we suggest that prevention efforts should target these populations because of the high risk, and at the same time those initiatives should be sustained over time."
Suicide risk and prevention have been much discussed topics since Germanwings co-pilot Andreas Lubitz apparently slammed the Airbus A320 he was flying into a mountain in the French Alps on March 24, killing all 150 aboard.
It's not known if Lubitz had previously attempted suicide, but authorities say the 27-year-old had received psychotherapy before obtaining his pilot's licence and his medical records referred to "suicidal tendencies."
Subsequent visits to doctors showed no record of any propensity for self-harm or aggression towards others. However, ripped-up sick notes from doctors — including one that would have kept the co-pilot off work the day of the crash — were found in his Dusseldorf apartment.
Lufthansa, which owns Germanwings, said Tuesday that the company knew in 2009 that their employee had suffered an episode of "severe depression" before finishing flight training, but that he had since passed all medical checks.
Finkelstein was reluctant to comment directly on Lubitz's case, in part because there are so many unknowns, including whether he had tried earlier to take his own life.
"But I think what (ties in) with our data is the fact that the risk is durable — and years after, it came back," he said.
Factors that increase the risk of suicide are advancing age, being male, high socioeconomic status and a diagnosis of depression and psychiatric care in the year preceding the first attempt, he added.
The study also found that initial self-poisoning attempts were associated with a 10 times higher risk of accidental death over the following decade, often due to falls from heights or motor vehicle crashes, without a suicide note.
"We suspect that some accidental deaths or deaths of indeterminate intent are in fact suicides that were not classified as such by investigating coroners in the absence of definitive proof of intent," the authors write.
Dr. Jennifer Brasch, a psychiatrist in the Concurrent Disorders Clinic at St. Joseph's Healthcare in Hamilton, said the study's finding that an unsuccessful attempt continues to put a person at high risk for suicide "should be a flag to every doctor."
"People need a primary-care physician or psychiatrist or psychiatric clinic that provides ongoing followup," said Brasch, who was not involved in the study.
There are also interventions that have been shown to help prevent a subsequent suicide attempt from occurring, including hospital-based programs that teach patients how to combat suicidal thoughts and develop problem-solving skills, as well as offering peer support, she said.
—With files from Associated Press
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