A causal link has been identified between traumatic brain injury and post-traumatic stress disorder.
Research also suggests that those with mild traumatic brain injury are more likely to develop an anxiety disorder.
Consequently, those with traumatic brain injury are being advised to take precautions to limit the number of times they are exposed to stressful situations.
The discovery was made in an animal study designed to separate physical and emotional traumas.
Researchers trained rats using fear conditioning two days after they experienced a concussive brain trauma.
It was found that rats with traumatic brain injury experienced more fear than those without it.
"Something about the brain injury rendered them more susceptible to acquiring an inappropriately strong fear. It was as if the injury primed the brain for learning to be afraid," explained Dr Michael Fanselow, lead author of the study.
Post-traumatic stress disorder is often common in veterans and those who have been involved in a serious accident.
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