CTE and Violence: Did Brain Damage Play a Role in the Manhattan Office Shooting?

The tragic mass shooting in Midtown Manhattan on July 28, 2025, where a gunman opened fire in an office building, killing four people and wounding another before taking his own life, has ignited a critical discussion about the potential link between chronic traumatic encephalopathy (CTE) and violent behavior. The shooter, 27-year-old Shane Tamura, a former high school football player, left behind a note referencing CTE and expressing anger towards the NFL, which has offices in the building. In September 2025, the New York City medical examiner announced that an autopsy revealed “unambiguous diagnostic evidence” of low-stage CTE in Tamura’s brain. This revelation has intensified the debate surrounding CTE and its possible role in violent acts, raising complex legal and ethical questions.

Understanding CTE

Chronic Traumatic Encephalopathy (CTE) is a neurodegenerative disease associated with repeated head injuries. It is often found in athletes participating in contact sports like football, boxing, and hockey, as well as in military personnel and others who have experienced repetitive brain trauma. CTE can lead to a range of symptoms, including:

Memory loss
Difficulty concentrating
Impulsivity
Aggression
Depression
Dementia
Suicidal thoughts

The disease is characterized by the accumulation of abnormal tau protein in the brain, which disrupts normal brain function. Currently, CTE can only be definitively diagnosed through a post-mortem autopsy.

The Link Between CTE and Violence: A Complex Relationship

The question of whether CTE can cause violent behavior is a subject of ongoing research and debate. While some studies and case reports have suggested a link between CTE and aggression, impulsivity, and other behavioral changes, the relationship is complex and not fully understood.

Studies Suggesting a Link: Some studies have found a higher prevalence of behavioral issues, including aggression and impulsivity, in individuals diagnosed with CTE. A 2024 study published in Neurology found that people with CTE who also had a family history of mental illness were at a higher risk of aggression in middle age.
Studies Questioning a Direct Causal Relationship: Other research has questioned the direct causal relationship between CTE and violence. Some experts argue that other factors, such as genetics, mental health history, substance abuse, and environmental influences, may play a more significant role in violent behavior.
Lack of Definitive Evidence: It’s important to note that CTE is a complex disease, and its effects can vary widely from person to person. Not everyone with CTE will exhibit violent behavior, and many individuals with a history of head trauma and behavioral problems do not have CTE.

CTE as a Legal Defense?

The potential link between CTE and violent behavior has led to discussions about whether CTE could be used as a legal defense in criminal cases. The argument is that if an individual’s violent actions were influenced by brain damage caused by CTE, they may not be fully responsible for their actions.

Challenges in Using CTE as a Defense: There are significant challenges in using CTE as a legal defense. One major obstacle is that CTE can only be definitively diagnosed post-mortem. This makes it difficult to prove that a living defendant has CTE and that the disease directly caused their violent behavior.
Other Factors to Consider: Even if a defendant is diagnosed with CTE, it is still necessary to prove that the brain damage specifically impaired their judgment and ability to control their actions to the extent that they lacked the intent to commit the crime. Other potential causes for CTE-like symptoms must also be ruled out.
Legal Precedent: While there have been some cases where defendants have attempted to use CTE as a defense, its success has been limited. Courts have generally been cautious about accepting CTE as a sole or primary cause of criminal behavior, emphasizing the need to consider other factors and the lack of definitive scientific evidence.

The NFL’s Response and Legal Ramifications

The connection between CTE and football has led to increased scrutiny of the NFL’s handling of player safety and head injuries. In 2015, the NFL settled a lawsuit with former players for over \$1 billion, compensating those who suffered from CTE and other brain injuries.

Ongoing Litigation: Despite the settlement, legal battles related to CTE and the NFL continue. Some former players and their families are pursuing individual lawsuits against the league, alleging that the NFL concealed the dangers of head injuries and failed to adequately protect players.
Focus on Prevention: The NFL has implemented several rule changes and safety protocols aimed at reducing head injuries. However, critics argue that more needs to be done to protect players at all levels of the sport, from youth leagues to the professional ranks.
Legal Options: If a loved one suffered a fatal brain injury caused by CTE, you may be eligible to file a wrongful death lawsuit. Families could seek legal action if the brain trauma leading to CTE resulted from negligence, such as unsafe conditions in sports, work environments, or other activities where repeated head injuries were not properly managed.

The Importance of Awareness and Prevention

The Manhattan office shooting and the subsequent diagnosis of CTE in the shooter have highlighted the urgent need for greater awareness and prevention efforts related to head injuries and CTE.

Protecting Young Athletes: It is crucial to educate young athletes, parents, and coaches about the risks of head injuries in contact sports. Implementing stricter safety protocols, promoting proper tackling techniques, and limiting the number of head impacts during practice and games can help reduce the risk of CTE.
Early Detection and Intervention: Recognizing the early signs of CTE and seeking medical attention can help manage symptoms and potentially slow the progression of the disease. Further research is needed to develop reliable diagnostic tools for CTE in living individuals.
Supporting Research: Continued investment in CTE research is essential to better understand the disease, its causes, and its potential link to violent behavior. This research can help develop effective prevention strategies and treatments for CTE.

Seeking Legal Consultation

If you or a loved one has been affected by CTE, consulting with an experienced attorney is crucial to understand your legal rights and options. A lawyer can help you:

Investigate the cause of injuries and determine liability.
File legal claims and seek compensation for medical expenses, lost wages, and pain and suffering.
Navigate the complex legal landscape surrounding CTE and head injuries.

Conclusion

The Manhattan office shooting serves as a stark reminder of the devastating consequences of violence and the potential role that brain damage may play in such tragedies. While the link between CTE and violence remains a subject of ongoing research and debate, it is essential to take steps to prevent head injuries, promote awareness of CTE, and provide support for those affected by this debilitating disease. The legal implications of CTE are complex and evolving, and individuals and families affected by CTE should seek legal counsel to protect their rights and explore their options for seeking justice and compensation.