The gunman who opened fire in Midtown Manhattan on Monday, fatally shooting four people before taking his own life, left behind a note referencing chronic traumatic encephalopathy (CTE) multiple times, according to law enforcement sources familiar with the investigation.
Authorities believe the shooter was targeting the NFL headquarters, located in the Park Avenue building where the deadly incident occurred.
CTE is a progressive, degenerative brain disease linked to repetitive head trauma. Often associated with professional athletes in contact sports, the condition has been at the center of debates surrounding player safety and the long-term effects of concussions. While it can only be definitively diagnosed through a postmortem autopsy, it has become an increasing concern within the sports and medical communities.
In fact, a 2024 study found that one-third of retired NFL players suspect they may have CTE. The NFL first publicly acknowledged a connection between football and CTE in 2016.
The disorder has also been connected to tragic events in the past. Former NFL player Phillip Adams, for instance, was diagnosed with severe CTE after he fatally shot six people and then died by suicide in South Carolina in 2021.
To better understand the science behind the condition, NBC News consulted Dr. Aaron Lord, chief of neurology at NYU Langone Health, who specializes in traumatic brain injuries.
What Is CTE and How Does It Affect the Brain?
CTE was first identified in professional boxers and originally referred to as “punch-drunk syndrome.” According to Dr. Lord, it is now understood as a neurological disease that can lead to early-onset dementia, memory loss, mood swings, personality shifts, and movement disorders resembling Parkinson’s disease.
“It’s just about repetitive shock waves to the brain,” said Lord. While often associated with athletes, anyone experiencing repeated head trauma may be at risk.
Research is ongoing into CTE’s relationship with suicide and mental health, particularly in high-level athletes who later exhibit suicidal ideation or violent behavior. Although links are being explored, Lord cautions against drawing firm conclusions.
“It’s a new one we’re still defining,” he said. “We still don’t know the true incidence or prevalence of this disease.”
How Is CTE Diagnosed?
Currently, CTE cannot be diagnosed while a patient is alive. Even postmortem, diagnosis remains complex. According to Lord, pathologists must find distinctive patterns of brain tissue degeneration and abnormal protein clusters—particularly around blood vessels.
Some individuals may suspect they have CTE based on significant mood or personality changes, especially if they have a known history of concussions or brain trauma. MRI scans may reveal suspicious patterns, but these are not definitive for diagnosis.
CTE’s symptoms can also mimic psychiatric disorders such as depression, bipolar disorder, and schizophrenia, which further complicates diagnosis. Lord also noted that some patients with CTE exhibit homicidal thoughts and impulsivity, in addition to broader behavioral changes.
“Even a single traumatic brain injury, like one from a car crash, can cause long-term personality and impulse control issues,” Lord added, even if CTE does not develop.
Can CTE Be Treated or Prevented?
At present, there is no cure or direct treatment for CTE. However, psychiatric medications can help manage certain symptoms such as mood swings and behavioral disturbances.
According to the Mayo Clinic, not everyone who sustains a concussion develops CTE. The key, experts say, is prevention.
Dr. Lord emphasizes the importance of protective measures: wearing helmets during contact sports, using seatbelts, and avoiding repeated head trauma. “Prevention is the best medicine,” he said.
Context and Implications
The alleged shooter’s mention of CTE and apparent targeting of the NFL headquarters has reignited public concern over the neurological risks linked to professional sports. While it remains unclear whether the shooter had ever been diagnosed with or exhibited symptoms of the disease, the incident highlights the urgency of ongoing research, education, and mental health support for individuals at risk.
As investigations continue, the medical community continues to grapple with understanding a disease that remains elusive yet profoundly impactful.
Related topics:
