Specific Blood Protein Linked to Lower Risk of Depression and PTSD After TBI

A specific blood protein has been linked to a lower risk of depression and PTSD caused by traumatic brain injuries

Researchers at University of California San Diego School of Medicine and Veteran Affairs San Diego Healthcare System conducted a study of 1,025 Marines, identifying that active-duty marines with higher levels of the natural anti-NMDAR1 antibody had a lower risk of developing these conditions.

​It found that anti-NMDAR1, which targets NMDA receptors—key proteins in the brain responsible for storing new information and forming memories in the brain—had a huge impact
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Rates of PTSD and TBI in the Military

PTSD is a long-term mental health condition that plagues people with physical and mental symptoms, including flashbacks to traumatic events.

It is more common among veterans than civilians, as roughly 7 out of every 100 veterans will have PTSD at some point in their life, according to research by the Department of Veterans Affairs (VA). In the general population, 6 out of every 100 adults (or 6%) will have PTSD in their lifetime.

TBI, which occurs after a sudden blow to the head, can cause PTSD.

Between 2001 and 2025, roughly 556,502 veterans screened positive for TBI or a TBI-related diagnosis in VA medical records, or filed claims for VA disability compensation.

The Role of Anti-NMDAR1

Those with the most antibodies had about 25% lower depression symptom scores and 225 lower PTSD scores after deployment.

The researchers suspect that these antibodies are too large to fit into synapses, gaps between brain cells where chemical signals are transmitted. This, they hypothesize, might be why brain injury signals are not transmitted in those with high levels of anti-NMADR1 antibodies.

"We were excited to find that a naturally-occurring immune marker could act almost like a built-in protective factor against some of the most disabling consequences of brain injury,” said co-senior author Victoria Risbrough, professor and vice chair of academic affairs in the Department of Psychiatry at UC San Diego School of Medicine and VA Research Career Scientist at VA San Diego Healthcare System, in a statement.

“If we can understand how these antibodies work, it may open a new path toward identifying who is most at risk after a TBI, and eventually, toward new ways to intervene," she added.

The National Institutes of Health and the VA partially funded this study, conducted as part of the Marine Resiliency Study II—a long-term research project investigating PTSD risk factors.

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