CHICAGO No matter where in the world they live, people who are young, single, female, poorly educated or mentally ill are at higher risk of suicide, an international team of researchers reported on Thursday.
Their study, which includes data about nearly 85,000 people in 17 developed and developing countries around the world, reveals some consistent patterns.
They found 9.2 percent of people had seriously considered suicide, and 2.7 percent said they attempted it.
"Our research suggests that suicidal thoughts and behaviors are more common than one might think, and also that key risk factors for these behaviors are quite consistent across many different countries around the world," said Harvard University researcher Matthew Nock, whose study appears in the British Journal of Psychiatry.
According to the World Health Organization, suicide rates have increased by 60 percent in the last 45 years. Suicide is now among the leading causes of death among those aged 15 to 44 for both genders.
"Across every single country we saw there was a significant increase in suicidal thoughts during adolescence and young adulthood," Nock said in a telephone interview.
He said the odds of a person committing suicide rise sharply between the ages of 12 and 15 and the time between the first suicidal thoughts and an actual attempt is short.
"The highest-risk time for making a suicide attempt is within one year after a person first starts thinking about suicide. That happens 60 percent of the time or more across every country," Nock said.
The study also began to paint a portrait of common risk factors that emerged in nearly every country. They found people who aged 18 to 34, females, the poorly educated, those who are unmarried and those with a mental disorder are more at risk.
There were also some surprising differences.
In high-income countries such as the United States, mood disorders such as depression are the strongest risk factor. But in low and middle-income countries, impulse control disorders, substance abuse and anxiety disorders posed the greatest risk.
"People most often think of suicide among those who are depressed. We found the presence of other mental disorders also significantly increase the risk," Nock said.
While risk factors were similar, rates of suicidal thoughts and behaviors varied widely across the nations surveyed.
The study found that 3.1 percent of people from China reported suicidal thoughts, compared to 15.9 percent of those from New Zealand.
The researchers said this variation likely reflects different cultural views and stigmas.
The research was based on face-to-face interviews collected by the World Health Organization's World Mental Health Survey Initiative. Other countries included in the survey were, Nigeria, South Africa, Colombia, Mexico, the United States, Japan, Belgium, France, Germany, Italy, the Netherlands, Spain, Ukraine, Israel and Lebanon.
(Editing by Maggie Fox and Alan Elsner)