The mortality rate for suicide in the United States increased by 15 percent from 2000 to 2009, usurping traffic accidents as the top cause of injury-related deaths in 2009, according to findings published online in The American Journal of Public Health in September. The findings mirror trends in the European Union, Canada, China and the active U.S. military.

“I was expecting to see the suicide rate go up, but not for suicide to emerge as the leading cause of injury mortality,” says Ian Rockett, PhD, MPH, of West Virginia University, who led the study. Rockett and his team also found a 128 percent increase in the rate of deaths due to unintentional poisoning — mostly from prescription drugs such as opioids — and a 71 percent increase in the death rate from falls. Suicide and falls are now the third and fourth most common causes of injury deaths, bumping homicide into the fifth position.

While the good news is that the traffic crash death rate decreased by 25 percent, Rockett is concerned that the suicide rate is still underestimated. Too often, he says, intentional overdose deaths are misclassified as unintentional injuries, hindering prevention efforts.

“We need a whole lot more understanding of how someone makes the decision to end their life within the context of addiction,” he says. “Is there a line that gets crossed that’s in some way predictable?” That’s a question he hopes psychologists can help answer.

 —Anna Miller