A study released in the Canadian Medical Association Journal (CMAJ) has found concussions in adults may lead to an increased risk of suicide. The study looked at over 230,000 patients who had suffered a concussion and analysed how many deaths occurred within the group over a 20-year period.

Scientists found suicides took place at a rate of 31 deaths per 100,000, perhaps three times the national norm. They found concussions suffered at the weekend, in particular, brought an increased statistical risk of suicide in later life.

For a long time, doctors have known about the risks of head injury to those in the military, and of recent several high profile cases have shone a light on the world of sport, too. Concussion in a game of American Football or Rugby is relatively commonplace now, with an ever increasing emphasis on the power play, and bigger, stronger athletes were playing the game.

Protocol for dealing with head injuries at an elite level is much improved but the point remains a controversial one among fans of the match – and parents whose kids take part in impact sports.

The CMAJ study, though, focussed more on the civilian side of life, looking at concussions sustained by ordinary people, doing ordinary things. Donald Redelmeier, one of the study’s lead authors, told Scientific American that most of the people he saw were middle aged, and not “elite athletes.”

He said the most common circumstances for receiving a concussion were not from sports but vehicle accidents, DIY mishaps or other accidents during everyday life.

Authors say there is no precise answer as to a link between concussion and suicide, but they do have tentative hypotheses. One could be a certain predisposition towards depression. Another is that shock may cause a damaging inflammation of the brain which causes more damage than is currently recognised.

A third possibility has to do with recovery – it may be many people are not giving themselves adequate rest from their injury before hurling themselves back into the hurly-burly of modern life.