Now, a century after the first cases began to appear, scientists believe they have for the first time identified the signature brain injury that could explain why some soldiers go on to have their lives blighted by the condition.

After conducting autopsies on US combat veterans who survived improvised explosive device (IED) blasts in Iraq and Afghanistan but later died of other causes, researchers in the US found the ex-soldiers had a unique type of brain injury.  

Described as a ‘distinctive honeycomb pattern of broken and swollen nerve fibres’, the injuries were not the same as those found in car crash and drug overdose victims, or sufferers of punch-drunk syndrome, which is caused by repeated blows to the head.