The perpetrator responsible for the fatal shooting at a Midtown Manhattan office building in July has been posthumously diagnosed with chronic traumatic encephalopathy (CTE). This degenerative brain disease is strongly associated with repetitive head injuries sustained in sports like football, according to a report from the New York City medical examiner’s office.
CTE can only be confirmed after death. Shane Tamura, the gunman, took his own life following the violent incident at 345 Park Avenue.
The medical examiner’s official statement confirmed “unambiguous diagnostic evidence of Chronic Traumatic Encephalopathy… in the brain tissue of the decedent.” The findings indicated a “low-stage CTE, according to current consensus criteria.”
This discovery regarding Mr. Tamura’s brain condition revives pressing questions about the potential long-term risks associated with playing tackle football, even at just the youth level.
Mr. Tamura, whose football career did not extend beyond high school, left a note mentioning CTE. In it, he accused the National Football League (NFL) of prioritizing profits over player safety by allegedly concealing the dangers of brain trauma in the sport. Authorities indicated that he sought retribution against the league, whose headquarters are located in the targeted building.
Over the past two decades, numerous former athletes from football, boxing, and hockey have been diagnosed with CTE. This growing body of evidence has significantly increased public awareness of the inherent dangers in these sports, prompting researchers to deepen their understanding of the disease and its wide-ranging symptoms. However, leaders within the NFL and other sports organizations have often been reluctant to fully acknowledge the direct correlation between their sports and severe brain trauma.
CTE commonly impacts the superior frontal cortex, a crucial region for cognitive functions and executive processes like working memory, strategic planning, and abstract thought. The disease also frequently affects the amygdala, which plays a vital role in emotional regulation, aggression, and anxiety. Typical symptoms include challenges with impulse and aggression control, varying degrees of dementia, abrupt mood changes, impaired judgment, and disorganized behavior.
While most documented cases of CTE have involved athletes who participated in contact and collision sports for 15 to 20 years—likely enduring thousands of head impacts—researchers caution that studies on CTE are subject to selection bias. This is because families are more likely to donate the brains of loved ones who displayed symptoms of neurological decline.
As scientific understanding of CTE advances, more families are donating the brains of younger athletes. Some of these younger individuals have also been found to have CTE, generally at less severe stages than older athletes. Mr. Tamura, who was 27, represents another addition to this expanding group of younger individuals diagnosed with the condition.
Despite the accumulating evidence, researchers maintain a cautious stance on directly attributing specific actions, such as murder or suicide, solely to CTE, recognizing that multiple factors can contribute to such complex behaviors.
Dr. Ann McKee, who directs the Boston University CTE Center and has extensively studied brains from athletes, soldiers, and others with brain trauma, has emphasized the limited understanding of the precise link between violent impulsive behavior and CTE, calling for more research in this area.
Dr. McKee recently noted that “damage to the frontal lobes, which can damage decision making and judgment,” and also “cause impulsivity and rage behaviors, so it’s possible that there’s some connection between brain injury and these behaviors.”
Several high-profile cases involving former football players who committed violent crimes have drawn significant national attention. Notably, Aaron Hernandez, a former New England Patriots tight end, was convicted of murder and later died by suicide in jail. Hernandez, who was 27 at the time of his death, was found to have a severe form of CTE, with damage comparable to that seen in players well into their 60s.
Similarly, Phillip Adams, who fatally shot six people before taking his own life in Rock Hill, S.C., in 2021, also had an “unusually severe” form of CTE. Adams was 32 and had played six seasons in the NFL.
Other former NFL players who died by suicide, such as Dave Duerson, deliberately aimed for their chests to preserve their brains for scientific study. Duerson explicitly requested that his brain be examined for signs of CTE.
However, researchers stress that these high-profile cases do not necessarily reflect the broader population of individuals living with CTE.
“I would never draw a direct line between someone’s brain pathology and any specific violent act, because the majority of people who have C.T.E. never committed anything like this,” stated Dr. Daniel H. Daneshvar, chief of brain injury rehabilitation at Harvard Medical School.
Historically, the risk of developing CTE was thought to be confined to those who endured years of professional contact sports like football, rugby, or boxing, absorbing countless blows to the head. Yet, recent diagnoses in younger athletes across various contact sports, including some who never reached professional or even collegiate levels, have broadened this understanding.
A 2023 study from Boston University investigated the brains of 152 contact-sport athletes who died before age 30, whose families had raised concerns about brain disease. Over 40 percent of these athletes showed evidence of CTE. The majority had played no higher than high school or college football, with 48 of the 63 CTE-diagnosed individuals having played football.
These younger athletes exhibited tau protein deposits in specific brain regions, a hallmark of CTE, similar to older athletes. However, the tau concentration was lower, and their cognitive symptoms mirrored those of other youth athletes without a CTE diagnosis. This suggests that the lesser tau accumulation might not be the primary driver of symptoms in these younger individuals, implying other contributing factors, researchers explained.
“The message here is that there’s less scientific understanding of what’s driving the symptoms in these younger players, and whether it’s related to brain trauma or perhaps other things,” commented Gil Rabinovici, a professor of neurology and radiology at the University of California, San Francisco. He is currently working on imaging techniques to diagnose dementia and CTE in living patients. “It’s going to be important to look at other brain changes that are not tau related. We should be very cautious in trying to attribute their behavior to what we find in the brain.”
In the absence of a definitive diagnostic test for CTE in living individuals, athletes like Mr. Tamura might conclude that their cognitive issues stem from the disease. Dr. Rabinovici referenced a survey of 4,180 former professional football players, where 34.4 percent believed they had CTE based on symptoms such as headaches, cognitive difficulties, depression, and suicidal ideation.
Mr. Tamura was on prescription medication for anxiety, depression, and bipolar disorder, according to his mother and New York police officials. His suicide notes revealed an intense preoccupation with brain injuries, and he attributed his deteriorating mental health to playing football and enduring repeated head impacts.
Dr. Rabinovici and other researchers have dedicated years to developing a reliable test for CTE in living patients. Promising avenues include blood tests and advanced brain imaging capable of detecting the tau protein in specific brain regions. Progress toward a solution, he noted, is “slow and steady.”
Following years of public relations challenges and increasing evidence linking football to CTE, the NFL’s top health and safety official finally acknowledged this connection in 2016. Since then, the league has actively promoted safer tackling techniques and encouraged participation in flag football, aiming to divert children from the conventional, higher-impact form of the sport.