In a somber development following the tragic July shooting at a Midtown Manhattan office building, the New York City medical examiner’s office has confirmed that the gunman, Shane Tamura, was suffering from chronic traumatic encephalopathy (CTE). This degenerative brain disease is closely associated with repeated head trauma, commonly seen in contact sports like football.
CTE, a condition diagnosable solely after death, was identified in Tamura following his suicide, which occurred after he carried out the attack at 345 Park Avenue.
A statement from the medical examiner’s office revealed “unambiguous diagnostic evidence” of CTE in Tamura’s brain tissue. The findings indicated a “low-stage” classification based on established criteria for the disease.
This diagnosis in Tamura reignites pressing questions about the potential long-term risks associated with playing tackle football, even for athletes who don’t continue past high school.
Tamura, a former high school football player, left behind a note mentioning CTE. In it, he accused the NFL of deliberately hiding the risks of brain trauma for financial gain. Police believe his rampage at the building, which houses the league’s headquarters, was an act of vengeance.
Over the last two decades, a growing number of former athletes—including football, boxing, and hockey players—have been diagnosed with CTE. This alarming trend has significantly boosted public awareness and scientific understanding of the disease and its devastating symptoms. Despite the mounting evidence, leaders within the NFL and other professional sports organizations have often hesitated to fully acknowledge the direct connection between their sports and brain trauma.
CTE typically impacts the superior frontal cortex, a crucial region for cognitive processes like working memory, planning, and abstract reasoning. It also frequently affects the amygdala, which plays a vital role in emotional regulation, aggression, and anxiety. Individuals with CTE commonly experience symptoms such as difficulty controlling aggression and impulses, mild dementia, severe mood swings, poor judgment, and disoriented behavior.
Historically, CTE diagnoses have predominantly occurred in athletes who participated in high-impact sports like football for 15 to 20 years, enduring countless head impacts throughout their careers. Researchers, however, emphasize a critical selection bias in CTE studies: most brain donations come from families whose loved ones displayed symptoms, potentially skewing the prevalence rates.
With increasing awareness, families are now donating the brains of younger athletes, leading to more CTE diagnoses in this demographic, though typically at less severe stages compared to older players. At just 27, Shane Tamura tragically becomes part of this expanding group.
Despite these findings, experts remain cautious about directly attributing specific actions, especially violent ones like murder or suicide, solely to CTE, recognizing that numerous other psychological and environmental factors can play a significant role.
Dr. Ann McKee, director of the Boston University CTE Center, a leading researcher in brain trauma studies involving thousands of athletes and soldiers, highlights the limited understanding of the direct link between violent, impulsive behavior and CTE, stressing the urgent need for further investigation.
She recently explained that “damage to the frontal lobes can impair decision-making and judgment.” She added, “It can also cause impulsivity and rage behaviors, so it’s possible that there’s some connection between brain injury and these behaviors.”
National attention has been drawn to several high-profile cases involving former football players and violent crimes, including Aaron Hernandez, the New England Patriots tight end. Hernandez was convicted of murder and later committed suicide in jail. Despite dying at age 27, his brain showed a form of CTE so severe it resembled that of players in their sixties.
Similarly, Phillip Adams, who committed a mass shooting in Rock Hill, S.C., in 2021, killing six people before taking his own life, also had an “unusually severe” form of CTE. He was 32 and had played six seasons in the NFL.
In other instances, former NFL players, such as Dave Duerson, who died by suicide, intentionally shot themselves in the chest to ensure their brains could be preserved for scientific study, explicitly requesting CTE research.
However, researchers caution that these highly publicized cases do not necessarily reflect the experiences of the wider population living with CTE.
Dr. Daniel H. Daneshvar, chief of brain injury rehabilitation at Harvard Medical School, recently stated that he would “never draw a direct line between someone’s brain pathology and any specific violent act, because the majority of people who have CTE never committed anything like this.”
For a long time, CTE was thought to primarily affect professional athletes in sports like football, rugby, or boxing who endured years of repetitive head trauma. However, recent findings reveal diagnoses in younger athletes across various contact sports, even those who never reached professional or even collegiate levels.
A significant 2023 study from Boston University examined the brains of 152 contact-sport athletes who passed away before age 30, whose families harbored concerns about brain disease. Over 40 percent of these athletes showed evidence of CTE. Most had competed only at high school or college levels, with football accounting for 48 of the 63 CTE diagnoses.
Similar to older athletes, these younger individuals exhibited tau protein deposits in specific brain regions, a hallmark of CTE. However, the tau concentration was lower in younger brains, and their cognitive symptoms mirrored those of other young athletes without CTE. This suggests that the reduced tau might not be the sole cause of symptoms in this group, indicating that other contributing factors could be at play, according to researchers.
Gil Rabinovici, a professor of neurology and radiology at the University of California, San Francisco, who is actively developing imaging techniques for diagnosing dementia and CTE in living patients, noted, “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.” He emphasized, “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.”
Without a definitive diagnostic test for CTE in living individuals, athletes, much like Tamura, may wrongly attribute their cognitive difficulties to the disease. Dr. Rabinovici referenced a survey revealing that 34.4% of 4,180 former professional football players believed they had CTE, based on symptoms such as headaches, cognitive impairment, depression, and suicidal ideation.
According to his mother and New York police officials, Tamura was prescribed medication for anxiety, depression, and bipolar disorder. His suicide notes clearly showed an intense preoccupation with brain injuries, as he firmly believed his deteriorating mental health stemmed from playing football and the cumulative effect of head impacts.
For years, Dr. Rabinovici and his colleagues have been diligently working to develop a reliable test for CTE in living patients. Promising avenues include blood tests and advanced brain imaging capable of detecting the tau protein in targeted brain areas. He describes this crucial research as “slow and steady.”
Following years of public relations challenges and overwhelming evidence connecting football to CTE, the NFL’s chief health and safety official finally acknowledged the link in 2016. Since then, the league has actively encouraged children to explore alternatives to traditional tackle football, advocating for safer tackling techniques and promoting flag football as a less impactful option.