Can Concussions Lead to Depression?

When Junior Seau died in May of 2012, the news landed hard for anyone who had watched him play. The San Diego Chargers linebacker, nicknamed the Monster in the Middle, had built a reputation on a ferocious defensive style over roughly twenty years in the National Football League. He took his own life at 43. His family then gave his brain to the National Institutes of Health so researchers could examine it.

Those independent researchers determined that Seau had chronic traumatic encephalopathy, or CTE. The disease is degenerative and grows out of repeated head trauma, including the kind of concussions athletes pick up in contact sports. Something similar had been noticed as far back as the 1920s, when boxers who slurred their words, shook, and seemed perpetually confused were called punch drunk. What drives the condition is a buildup of an abnormal protein called tau. The tau gathers around injured tissue and keeps the brain from working the way it should. Seau's brain showed exactly that cellular damage, and researchers have tied it to his death.

Depression itself is not listed as a symptom of CTE. The trouble is more indirect. Many of the difficulties the disease produces can push a person toward depression, and the symptom picture overlaps with Alzheimer's, a form of dementia that frequently brings depressive symptoms along with it. There is also a broader pattern in the research: repeated concussions and head injuries appear capable of causing lasting pathological change. People who develop post-concussion syndrome, meaning problems that linger after a concussion for any stretch of time, carry a higher risk of both depression and dementia than people who have not been hurt that way.

The picture gets more unsettling with younger people. Teenagers seem to face a steeper chance of depressive symptoms after a concussion than adults do.

A team at the University of Kentucky in Lexington looked into this by following 37 teenagers for 37 days after each had a concussion. None of them had reported psychological problems beforehand. By the end of the tracking period, 22 of the 37 were showing something new: irritability, anxiety, apathy, or depression.

Data from the University of California, San Diego points in a similar direction and is arguably more worrying. Jeffrey Max, M.D., a psychiatrist who specializes in traumatic brain injuries in children and teens, led that work. He reported that roughly 10 percent of the kids had a full depressive disorder or a subclinical one six months out from the concussion.

A separate study in the Journal of Adolescent Health found that a past concussion can raise a teenager's odds of depression considerably. Drawing on the 2007-2008 National Survey of Children's Health, the researchers calculated that young people aged 12 to 17 with a concussion history were three times as likely to report depressive symptoms. The numbers climbed higher for children dealing with additional risk factors like family history or poverty, but those added factors did not erase the underlying link between concussion and depression.

Sara Chrisman, M.D., a pediatrician at Seattle Children's Hospital, has said the findings concern her. A concussion rarely arrives alone for a child. The event can bring its own stressors: fear of hospitals and doctor visits, or a stretch of social isolation while the child sits out and recovers.

Recovery timelines complicate things further. High school students generally need longer to bounce back than college students and adults. Girls appear to take longer than boys, though researchers have not pinned down why. And even among children, doctors cannot always explain the variation. Some recover quickly while others drag on far past what anyone expected at first. One theory is that teenagers may stay quiet about what they are feeling, or shrug off warning signs that an adult would flag.

Signs of a concussion or other brain injury tend to surface in a few areas. On the cognitive side, memory suffers, especially short-term memory. Sleep patterns shift too, with some teens sleeping much more or much less than usual and others struggling to fall asleep at all. The disorientation these injuries cause is part of why they are easy to miss.

Since teens may not recognize their own symptoms as serious or raise them with an adult, the responsibility often falls to parents, coaches, and teachers to spot the warning signs instead. Watching for the physical effects gives adults a chance to help a child heal well and, with luck, head off something worse like depression. If a coach or parent thinks a child has a concussion, the standard medical advice is to pull the child from play right away and keep them from activity until a doctor has examined them. Rest matters, and it can help to build a recovery plan together with the teen's teachers.

Prevention deserves attention too, in games and in gym class alike. Teaching students, parents, and coaches about what causes concussions and why they are dangerous should make play safer over time. The right protective equipment can also be the line between a serious injury and one that only keeps an athlete off the field for a little while.

- Melissa Lavery, M.S.