Some concussion symptoms that last three months after a head injury may be related to post-traumatic stress disorder, a new study suggests.

Mild traumatic brain injury accounts for more than 90 per cent of brain injuries, according to an international review for the World Health Organization, but little is known about prognosis.

TMR car accident

Road crashes were the source of many of the head injuries suffered by patients in the study group. (Radio-Canada)

In Wednesday’s issue of the journal JAMA Psychiatry, Emmanuel Lagarde of the University of Boredeaux, David Cassidy of Toronto Western Research Institute and their team focused on 534 patients with head injuries and 827 control patients with non-head injuries who went to an emergency department in France.

Concussions or mild traumatic brain injury can lead to three different types of symptoms:

  • Physical, such as headache and nausea.
  • Cognitive, such as memory or attention problems.
  • Behavioural such as depression, anxiety and irritability.

During the three-month followup, 21 per cent of the patients with head injuries and 16 per cent of the patients with non-head injuries met the criteria for a diagnosis of post-concussion syndrome.

Nearly nine per cent of patients with head injuries met the criteria for PTSD compared with two per cent of patients in the control group.

In a statistical analysis, having a mild traumatic brain injury was a predicator of PTSD, but not post-concussion syndrome.

"Available evidence does not support further use of post-concussion syndrome. Our results also stressed the importance of considering PTSD risk and treatment for patients with mild traumatic brain injury," the researchers concluded.

Jane Topolovec-Vranic, a clinical researcher in mild traumatic brain injury and neuroscience at St. Michael’s Hospital in Toronto, said the study was well done with rigorous analyses and a control group that is often missing in such studies.

Topolovec-Vranic notes many people recover but she hopes that the findings help to increase awareness of the range of symptoms of concussions that can occur after a hit to the head.

"They may dismiss it or not even seek medical attention thinking that they'll recover just fine. This study is suggesting they need to keep an eye out for symptoms that might be happening after a mild traumatic brain injury," Topolovec-Vranic said.

The research was funded by Inserm, the Reunica Group and Bordeaux University Hospital in France.

With files from CBC's Amina Zafar