TORONTO, Feb. 8 (UPI) -- Adults who have concussions are at three times greater risk for suicide if the injury is sustained on a weekday and four times greater risk if it happens on the weekend, according to a new study.
University of Toronto researchers said the increased risk for suicide also increased with each concussion a person had, and that risk increased regardless of any other demographic factor.
"We know that a concussion can cause lasting changes in the brain that can alter mood, perhaps resulting in behaviour changes including impulsivity," Donald Redelmeier, a researcher and physician at Sunnybrook Research Institute, said in a press release. "It's possible that we're seeing greater suicide risk linked to weekend concussions due to risk-taking associated with recreation or misadventure, whereas weekday injuries may be linked to employment hazards. We may also be seeing an effect of self-blame if the injury event was self-initiated."
For the study, published in the Canadian Medical Association Journal, researchers reviewed medical records for 235,110 concussion patients diagnosed in Ontario between 1992 and 2012.
The researchers found 667 suicides during a median follow-up of 9.3 years -- about 31 out of 100,000 people per year, a rate three times higher than in the overall population.
"Understanding how a history of concussion raises the risk of suicide, and supporting patients with better screening, treatment and follow-up for recovery may be important steps in preventing these tragic and avoidable deaths," said Redelmeier.