Originally published on 7/30/25

On July 28, 2025, a deadly shooting at a New York City office building—home to both the National Football League (NFL) headquarters and investment firm Blackstone—left five victims dead, including the gunman, Shane Tamura. In a note left behind, Tamura blamed the NFL for his deteriorating mental health and requested that his brain be studied for chronic traumatic encephalopathy (CTE), the degenerative brain disease often linked to repeated head trauma.

Although authorities confirmed Tamura had no professional football experience and no formal CTE diagnosis at the time of the attack, the note reignited urgent questions about the disease’s potential role in mood disorders, cognitive decline and violent behavior. So, what exactly is CTE—and how can you recognize its early signs or reduce your risk? Here’s what to know.

Signs and symptoms of chronic traumatic encephalopathy—CTE

CTE is a brain disease that, according to the Mayo Clinic, is “likely caused by repeated head injuries.” 

It is most common in former football players, with a 2024 JAMA Neurology study claiming that “approximately 34% of former professional ASF [American-style football] players reported perceived CTE.”

Mayo Clinic added to that, saying that “It also may occur in military members who were exposed to explosive blasts.” 

The most common and recognizable symptoms for CTE include shifts in mood, behavior and in some cases motor problems and psychotic symptoms, most of which occur after someone suffers from multiple different head injuries. They appear in four stages, with the fourth one being when people begin to become paranoid and have difficulty speaking. 

“[It] usually begins in small spots in the frontal lobes,” Dr. Anne McKee, the director of the CTE Center at Boston University, told CBS News. “But over time, with aging, it starts affecting widespread regions of the brain and can cause profound memory loss and even dementia.” 

However, despite those easy-to-recognize symptoms, Mayo Clinic says, “CTE is rare and not well understood, but experts don’t believe it’s related to a single head injury.” 

“Experts are still trying to understand how repeated head injuries and other factors might contribute to the changes in the brain that result in CTE,” the international hospital chain continued. “Researchers are looking at how the number of head injuries someone experiences and how bad the injuries are may affect the risk of CTE. Experts also don’t yet know how often CTE occurs in the population.” 

Like many neurodegenerative diseases, CTE can only be definitively diagnosed after death. In some cases, individuals experiencing unexplained mood shifts, paranoia or psychological distress have expressed concern over their brain health before taking drastic action—including requesting post-mortem analysis. While troubling, these instances highlight the urgent need for earlier detection and intervention.

“We have seen individuals with CTE that have had substantial breaks with reality,” Dr. McKee said. “There’s precedence where a former football player has a break of homicidal violence, and this kind of behavior is obviously something we need to prevent.”

How to reduce your risk of CTE 

According to Mayo Clinic, CTE “can be prevented by lowering the risk of getting a concussion. People who have had one concussion are more likely to have another head injury. The current recommendation to prevent CTE is to reduce mild traumatic brain injuries and to prevent additional injury after a concussion.” 

As of publication, there is no cure for CTE, but researchers are actively working on creating one. They are also working on figuring out how to diagnose the disease in a living person, since as of now, they can only do it “by examining samples of a person’s brain with a microscope. But they can only do this during an autopsy after someone dies,” per the Cleveland Clinic. 

Despite that, though, the clinic does say that “Even though your provider can’t definitively diagnose CTE while you’re alive, they can still make an educated assumption. They’ll build a diagnosis using a few factors [such as] a physical exam, a neurological exam, the symptoms or changes you’re experiencing and your medical history—especially if you know you’ve had head injuries.” 

If you or someone you know is struggling with mental health and/or suicidal thoughts, call the National Suicide Prevention Lifeline at 988.

Link to original: https://www.womansworld.com/wellness/mental-health/cte-symptoms-that-mimic-dementia-what-to-watch-for