Mind & Brain / Mental Health

Some 20 years ago, in front of a frenzied and antagonistic crowd, Harry Carson hurled his entire bulk—240 pounds—into an equally massive human body racing toward him across the field at Washington’s RFK Stadium. A middle linebacker with the New York Giants, Carson was a celebrated defensive football player, smart and agile, selected for the Pro Bowl even during years his team couldn’t eke out a winning season. Above all, he was known for aggression. Once, walking off the field after a game, Carson felt a tug on his jersey, turned around, and found himself eye to eye with O. J. Simpson. “Man, I’ve been hit by some of the best,” the running back told him. “But I’ve never been hit as hard as you hit me today.”

That day at RFK Stadium, Carson’s quarry was John Riggins, a Washington Redskins fullback with a similar reputation. Helmet against helmet, shoulder against shoulder, the players crashed with a concussion-producing impact that Carson would remember for decades. “It was like two trains colliding,” he would later say. Dazed, Carson dusted himself off and walked back into the Giants’ huddle—and as he stood holding his teammates’ hands, everything went black. He didn’t faint. He didn’t stop playing. For a few minutes, though, he found himself unable to interpret his coach’s signals from the sidelines. He couldn’t call the next play, as the middle linebacker is expected to do. He just remained in the game, doing the best he could until he regained his wits.

Collegiate hit list advertisement | article continues below FOOTBALL 2002-03 Concussions: 3.52 per game/ practice per 1,000 athletes Three Most Common Injuries: Knee, 17%; upper leg, 14%; ankle, 11%. Total injuries: 3,057.   BASEBALL  2002-03 Concussions: No data available Three Most Common Injuries: Shoulder, 23%; elbow, 11%; upper leg, 10%. Total injuries: 275.   ICE HOCKEY  2002-03 Concussions: 2 per game/ practice per 1,000 athletes Three Most Common Injuries: Ankle, 14%; shoulder, 13%; knee, 10%. Total injuries: 114.   MEN’S SOCCER  2002-03 Concussions: 1.13 per game/ practice per 1,000 athletes Three Most Common Injuries: Upper leg, 21%; ankle, 18%; knee, 14%. Total injuries: 561.   WOMEN’S SOCCER  2002-03 Concussions: 1.8 per game/ practice per 1,000 athletes Three Most Common Injuries: Upper leg, 25%; ankle, 21%; knee, 16%. Total injuries: 723. All statistics from the National Collegiate Athletic Association.

Blackouts like these were becoming familiar sensations for Carson. Over 13 seasons, he estimates he received between 15 and 18 concussions. It was only toward the end of his career that he began to exhibit the cumulative effects of all these hits, signaling what his doctors would later call postconcussion syndrome. Carson developed headaches and muscle twitches. He grew sensitive to bright lights and loud noises, making it difficult for him to sit in a busy restaurant or do a television interview. He’d lose track of time: “It’d be Monday, and before I knew it, it’d be Thursday afternoon, and I didn’t fully understand what had transpired.” And then came the depression, hitting once or twice a month for no obvious reason. One day, while approaching New York’s Tappan Zee Bridge on his way to Giants Stadium, Carson’s mind took a macabre turn. “I should just drive the car right off the bridge,” he thought to himself. “All I have to do is just accelerate, go right through the guardrail, and that would be it.”

Until recently, athletes like Carson—alive and able bodied—were of little interest to scientists. With dozens of football fatalities each year in the 1960s, particularly at the high school level, researchers were much more concerned with on-field catastrophes. “When someone dies, that catches everyone’s attention,” says neurosurgeon Robert Cantu, medical director of the National Center for Catastrophic Sports Injury Research. “It’s not surprising that fatalities in football have been tracked since 1931.”

Thanks to better protective equipment and safer coaching techniques, football deaths have now dropped to single digits each year. The decline has allowed scientists to focus on more subtle traumas, and concussions are chief among them. For decades, neurologists and sports-medicine researchers considered their long-term effects negligible, but recently they’ve discovered that these “mild” injuries aren’t so mild after all. Preliminary results show that even a minor ding can trigger a neurological cascade that can eventually cause cognitive dysfunction and mental illness. Among retired football players who have sustained three or more concussions, 20 percent have been diagnosed with clinical depression—more than three times the rate of players who never got a concussion. Almost half of those are taking antidepressant medications, and most report that the condition impedes their normal daily activities, such as shopping for groceries and going to work.

All of this begs the question: Are the country’s most popular sports a hazard to brains as well as bodies? Every year, millions of children join Pee Wee football and soccer programs. For them, are the exercise and camaraderie of contact sports worth the risk of lifelong depression and mental disability?

During the 1970s and 1980s, scientists knew little about what happened inside the brain during assaults like those Harry Carson sustained. Now the picture is starting to come into focus. At the UCLA Brain Injury Research Center, neuropsychologist David Hovda spent much of the 1990s examining rat brains in an effort to understand what happens after traumas that leave brain cells alive and the animals conscious. Immediately after a concussion, all the cells in the brain fire at once—a massive electrical discharge “like a miniseizure,” he says—indiscriminately releasing an excitatory neurotransmitter called glutamate, which in turn triggers brain cells to release potassium. As potassium rushes out of the cells, calcium rushes in and takes up residence in the mitochondria, the cells’ power centers. To restore imbalances, the brain needs considerable energy, which comes in the form of glucose (sugar). But the mitochondria, which are essential to glucose metabolism, have become impaired as a result of the excess calcium. This leads to what Hovda calls a “cellular energy crisis.” Just as the brain needs the fuel that glucose provides, that glucose has become less available.

An injured athlete may be oblivious to the neurochemical cascade inside his brain. “You can see a broken arm,” says Carson. “You can see a torn ligament in the knee. But with a concussion, you don’t see it.” The effects show up in statistical research.