MONDAY, April 28, 2003 (HealthDayNews) -- National Football League players who suffer multiple concussions run a much greater risk of clinical depression later in life, new research claims.
The study, presented April 28 at the American Association of Neurological Surgeons annual meeting in San Diego, raises questions about the potential long-term impact of concussions for these athletes. It also should serve as a warning to parents with children playing organized football, experts say.
Researchers from the Center for the Study of Retired Athletes at the University of North Carolina surveyed 2,488 retired NFL players, with an average age of 58 and 6.7 years of playing pro football.
Those who had three or more concussions in their pro careers were nearly three times as likely to suffer clinical depression than those who had no concussions, the study found.
"Our study underscores the importance of considering the long-term consequences of concussion," says study author Kevin Guskiewicz.
"I think the question here is whether we as clinicians are paying close enough attention to potential long-term consequences [of repeated concussions], and I think our study calls attention to the likelihood that there are long-term consequences with respect to depression," he says.
Guskiewicz says it's unclear why repeated concussions increase the likelihood of depression: "It's the question everybody wants answered, and we're trying to do it."
Hoping for answers, Guskiewicz says he and fellow UNC researchers plan a follow-up study of retired NFL players beginning this fall. Players will undergo tests measuring cognitive functions such as memory, mental processing speed and attention span. They'll also undergo magnetic resonance imaging (MRI) and blood tests that might reveal brain damage or genetic causes of depression.
Of the retired NFL players studied, 61 percent suffered one concussion; 24 percent, three or more concussions; and 12 percent, five or more. At least 70 percent of those who suffered concussions returned to play the same day as a concussion.
Earlier research, including a study last month by University of Pittsburgh Medical Center researchers, suggests athletes who return to play before fully recovering from a concussion increase the risk of much more serious, perhaps even permanent, brain damage.
Among the retired players with three or more concussions, nearly 21 percent had clinical depression later, compared with about 7 percent of those who had no concussions.
Of all the players, 263, or 11 percent, reported they had been diagnosed with clinical depression. Almost half of these players are still being treated with antidepressants and 64 percent said depression limits their daily activities.
While the study focused on NFL players, researchers say the findings could apply to many others who suffer concussions. In organized football for all age groups in the United States, as many as 240,000 players a year may suffer concussions, the U.S. Centers for Disease Control and Prevention says.
"There are implications beyond the NFL," Guskiewicz says of the link between multiple concussions and depression. "It's likely that these results could have a trickle-down effect to the college level, the high school level and the Pop Warner level, but more research will be needed."
Gary Pace, clinical director of the May Center for Education and Neurorehabilitation at the May Institute in Brockton, Mass., says he wasn't surprised by the reported link between concussions and depression.
Like the UNC researchers, he says determining the reasons will take more research.
Concussions, Pace says, can cause subtle problems in concentration, motor skills and memory, possibly making it harder for concussion victims to do things they once enjoyed such as reading, playing competitive sports or even carpentry. This, in turn, could contribute to depression, he says.
"Multiple concussions can be cumulative, and that's where the more significant deficits occur," Pace says. "We do know now that as a result of multiple concussions, the brain becomes more vulnerable to more long-term kinds of brain injuries, which results in some of the depression we see in individuals."
Determining whether depressed victims of multiple concussions are less responsive to antidepressants than other people could help distinguish whether the depression stems at least partly from loss of abilities, he says.
Pace says the new study's findings underscore the dangers of concussion, which could be greater in youngsters with still-developing brains.
"The point that we're always trying to drive home is that parents just really need to be sensitive to this issue of concussions," Pace says. "The message for parents is that you have to take any kind of concussion very, very seriously."
In the study, UNC researchers also looked at possible links between multiple concussions and Alzheimer's disease but found none.
More information
For more on sports-related concussions, visit the University of Pittsburgh. To learn about signs of a concussion, check with the American Academy of Family Physicians.
