Washington, January 17 (ANI): Professional football players may be at increased risk for depression as a result of suffering frequent concussions, according to two studies.

"Our study shows that athletes who have sustained concussions in early adulthood may be at a higher risk for developing depression as they age compared to the general population," said study author Nyaz Didehbani, PhD, of the Center for BrainHealth at The University of Texas at Dallas.

In the first study, researchers evaluated 34 retired NFL athletes with a history of concussion and 29 people of the same age from the general population with no concussion history. Participants were tested for depression. Concussions were retrospectively graded based on American Academy of Neurology guidelines. The researchers examined thinking skills, mood and the physical symptoms of depression.

The study found that those athletes who exhibited greater symptoms on the Beck Depression Inventory scored significantly higher than the minimal range for depressive symptoms. The Beck Depression Inventory measures symptoms related to thinking, mood and the physical signs of depression. The retired athletes included in the study reported an average of four concussions, reinforcing the correlation between depression scores and the number of lifetime concussions.

The second study included 26 retired NFL athletes. Of those, five had depression and 21 did not have depression. Diffusion tensor MRI brain scans were used to measure damage to white matter in the brain. White matter contains tissue and nerve fibers that help carry signals from one part of the brain to another. Damage to white matter occurs in traumatic brain injury and also has been seen in some people with depression.

By looking at the amount of white matter damage in one area of the brain, researchers could predict which former players had depression with 100 percent sensitivity and 95 percent specificity. Sensitivity is the percentage of actual positives that are correctly identified as positive, and specificity is the percentage of negatives that are correctly identified. The severity of the depressive symptoms was also associated with the degree of white matter damage in a wide range of brain regions.

The study will be presented at the American Academy of Neurology's 65th Annual Meeting in San Diego. (ANI)