The term CTE may be new to you, so we’ve put together answers to the questions we hear most. For more detail, see What is CTE and our Research summaries.
1. What is CTE?
CTE stands for chronic traumatic encephalopathy. It is a brain disease linked to repeated hits to the head, in which an abnormal form of the protein tau builds up and damages nerve cells. It gets worse over time and can affect memory, thinking, mood and behavior.
2. What causes CTE?
Repeated head impacts over months or years. In 2022 the National Institutes of Health formally recognized that CTE is caused by repeated traumatic brain injuries. Experts don’t believe a single head injury causes CTE.
3. Do you need concussions to get CTE?
No. Research shows that many smaller hits that never cause concussion symptoms, sometimes called subconcussive hits, can start the brain changes behind CTE. That’s why the number of hits over time matters more than any one injury.
4. Who can develop CTE?
CTE has been found most often in people with years of repeated head impacts: players of football, hockey, soccer, rugby and other contact sports, boxers and combat-sport athletes, and military service members exposed to repeated blasts. It has been found in amateur and youth athletes as well as professionals, and in women as well as men. Researchers are studying whether other groups with repeated head trauma are also at risk. Not everyone with repeated head impacts develops CTE.
5. What are the symptoms?
Symptoms usually appear years or decades after the head impacts. They can include memory and thinking problems that may progress to dementia, depression, impulsiveness, aggression, mood swings and, in some cases, movement problems. None of these is unique to CTE, and many have other, treatable causes.
6. How is CTE diagnosed?
Today CTE can only be confirmed by examining the brain after death, which is why families who donate a loved one’s brain to research are so important. Since 2021, doctors have had research criteria for diagnosing traumatic encephalopathy syndrome, the pattern of symptoms associated with CTE, in living people. Brain scans and blood tests that could detect CTE during life are being studied but aren’t ready for routine use.
7. Is there a cure?
Not yet, and there is no treatment proven to slow the disease. Many symptoms, such as depression, sleep problems and headaches, can be treated, so anyone experiencing them should see a doctor.
8. How can I lower the risk?
- Reduce the number of hits. Researchers say this matters most, especially for children and teens: limit full-contact practice, teach safer technique, and consider when children start tackle and collision sports.
- Take every head injury seriously. Anyone with a possible concussion should stop playing, be checked by a medical professional, and follow return-to-play rules.
- Use the right gear. Helmets protect against skull fractures and other serious injuries and are essential, but they cannot prevent every hit from affecting the brain.
9. Where can I learn more or get help?
Start with your own doctor or the medical professionals you already work with. Our Resources page lists organizations that support patients, families and caregivers, and you can sign up for our free Research & Media Alerts email to stay current.
10. What does the CTE Society do?
We help families, athletes, veterans and the public understand CTE. We follow the research, explain it in plain English with links to the original sources, and point people to trustworthy help. We don’t give medical advice. Learn more about us.
11. When was the CTE Society founded?
The CTE Society was founded in 2014.
12. How is the CTE Society funded?
The CTE Society is a privately funded 501(c)(3) tax-exempt nonprofit organization.
Last reviewed October 2026. This page is for general information and is not medical advice.
