It seems that scientists are uncovering long-term effects of traumatic brain injuries all the time. For example, a new study reveals evidence of a causal link between traumatic brain injuries and post-traumatic stress disorder.

The study, conducted at a university with the use of rats, uncovered the connection by training rats with fear conditioning two days after they suffered a concussive brain trauma. The intent of the study was to examine the association of brain injuries and PTSD among military veterans.

In the study, the rats who suffered a brain injury became more fearful than that rats that didn't. One scientist says that the injury appears to have almost "primed the brain" for developing fear.

Researchers also examined the rats' amygdala, the main center of the brain for fear learning. They found that there are more neurotransmitters to promote learning and that the amygdala is in an "excitable" state to acquire fear.

Scientists ultimately concluded that people who suffer a traumatic brain injury were put at higher risk of developing PTSD or other anxiety disorders. Anyone who suffers a significant brain injury, they say, should attempt to avoid stressful situations.

Just why a link exists isn't entirely clear. One explanation is that suffering such an injury is a frightening experience and the link is incidental, according to PsychCentral. Another possibility is that the link is, as one researcher puts it, "mechanistic."

Perhaps the findings will help in the treatment of those who have suffered a traumatic brain injury. If they are kept out of stressful situations, it's possible their time of recovery will be easier.

Source: PsychCentral, "Brain injury linked to higher risk for PTSD, anxiety disorders," Traci Pedersen, Feb. 19, 2012