Aging NFL players: Studies point to increased risk of depression

Football players may risk more than bruises and broken bones. Evidence is mounting that repeated concussions many pro athletes suffer can cause chronic traumatic encephalopathy (CTE), a degenerative brain disease marked by depression, dementia, and other Alzheimer's-like symptoms. But to find out the exact cause of CTE, researchers need to be able to study athletes' brains. That's where NFL players come in. Keep clicking to meet 13 players - some living and some deceased - who are in the vanguard of pro athletes to have donated or announced their intention to donate their brains to science.

(CBS News) The family of star linebacker Junior Seau filed a lawsuit against the NFL on Wednesday, saying his suicide was linked to brain disease caused by the violent hits to the head he suffered while playing. The lawsuit comes as two new studies show National Football League players appear to be at an increased risk of depression as they age, due to brain damage from concussions.

In a study published in the American Academy of Neurology, researchers compared retired NFL players, with a history of four concussions each, to non-athletes with no concussion history. The former players showed greater evidence of depression in their thinking, mood and physical symptoms.

A second study appearing in the same publication used MRI scans on 26 athletes. They measured damage to the white matter in the brain, an area typically affected by traumatic brain injury. Researchers could predict with nearly 100 percent accuracy which athletes suffered from depression.

The U.S. Centers for Disease Control and Prevention estimates that as many as 3.8 million sports concussions occur each year, and a series of high profile suicides and battles with depression have drawn attention to the serious risks posed by the injuries.

Gallery: NFL players donate brains to science

The effects on athletes could also provide insight into similar symptoms seen in members of the military and other occupations, such as oil drilling.

Most importantly, depression is treatable, so looking for it in those most at risk can save lives.

To see Dr. Holly Phillips' full report, as seen on "CBS This Morning," watch the video in the player above.