Researchers Discovered A Possible Clue To Mental Resilience After Brain Injury

Recovering from a traumatic brain injury (TBI) isn't always as simple as waiting for a headache to go away. While some people experience few lasting effects, others see impacts of the head trauma months later, manifesting in changes to mood, anxiety, or stress response.

Researchers analyzed data from 1,025 male Marine and Navy infantry service members who were followed before and after a seven-month deployment to Afghanistan.

Before deployment, researchers measured levels of an antibody called anti-NMDAR1 in participants' blood. Anti-NMDAR1 antibodies interact with a receptor in the brain involved in learning, memory, and communication between brain cells. Around 5 to 10% of people naturally carry these antibodies, and high levels can cause a rare autoimmune condition that affects the brain.

Among people with a history of TBI, those with higher levels of the anti-NMDAR1 antibody tended to have fewer depression and PTSD symptoms after deployment.

The people with the highest antibody levels had 22% fewer PTSD symptoms and 25% fewer depression symptoms than those with lower levels.

They were also less likely to have moderate-to-severe depression.

TBI can disrupt the brain's normal chemical balance, specifically when it comes to glutamate, a chemical that helps brain cells communicate. TBI can cause a rise in glutamate, and too much of this can become harmful to brain cells and contribute to inflammation.

The anti-NMDAR1 antibody interacts with a receptor involved in this process, so researchers think naturally higher levels of the antibody could help the brain handle some of the changes that follow an injury.

This study found an association, not cause and effect, and researchers still don't know exactly how the antibodies might influence the brain after a TBI. This means the study proposes an interesting theory, but researchers can't confidently say the antibody protects the brain.

There's no established way to safely increase anti-NMDAR1 antibody levels, so this isn't something to try to change with supplements or biohacks. Plus, all participants were male service members, so it's unclear whether the same association would appear in women or civilian populations. At this point, the finding is a research lead, not a treatment.