Originally published May 10, 2012 at 11:30 a.m., updated May 10, 2012 at 3:06 p.m.
Dr Michael Lobatz, Neurologist, Director of the Rehabilitation Center for Scripps Health
A study in January found ex-football players are 59 percent less likely to commit suicide than non-athletes of the same age.
But Michael Lobatz, director of the Rehabilitation Center for Scripps Health, said there is a link between depression and suicide and a link between brain injury and depression.
"If you have a brain injury, have depression, you are therefore at increased risk for the development of suicidal ideations, so there is a continuum there," he said. "But there are so many factors involved in why a person would get to that point that you really understand that that's an extraordinarily complex issue and you really need to be careful about the assertions that you make about that."
Lobatz said there are multiple types of brain injuries, including Traumatic Brain Injury, or TBI, and chronic traumatic encephalopathy, or CTE. He said TBI comes from one traumatic injury to the brain, while CTE is caused by multiple injuries to the brain and manifests as a degenerative process later in life.
He said CTE is like Alzheimer's or Parkinson's disease, where patients worsen over time.
"That's very different than a single brain injury where we typically expects patients to have their symptoms initially and then remain the same or get better over time," he said.
TBI is often seen in military veterans, while CTE more often impacts athletes like boxers and football players, he said. However, researchers are now exploring whether blast injuries might be causing CTE in veterans as well.
Lobatz said returning military who suffered concussions are now showing signs of memory and concentration loss, personality changes and headaches and dizziness.
Because returning veterans are still young, Lobatz said it is too soon to tell if they will develop CTE later in life, but added, "it's that group that we're very concerned about."
People with repeated brain injuries, including concussions, are especially at risk for developing CTE, Lobatz said. If Seau suffered from brain injury, it would likely be CTE.
Lobatz said among student athletes, playing football is the number one cause of concussions. The number two cause, he said, is cheerleading.
"And when you think about cheerleading, the acrobatics that are done by students today doing that, both male and female, there is an increased incidence of concussion related to that as well," he said.
Researchers hope to study Seau's brain to determine whether he suffered from CTE.