The Conversation
Hundreds of first responders have told me they remember exactly how they felt during the attacks on the World Trade Center, even 25 years later.
They tell me that they remember not being able to think, see or smell anything. They could only concentrate on digging and removing debris from the road. They couldn’t rest because those trapped under the rubble couldn’t wait. Death surrounded them on all sides, and the only thing they could do was do their best to contain it.
Although what happened on September 11 was unprecedented, similar tragedies occur quite frequently. As an occupational health physician working with 9/11 rescuers, it’s easy for me to imagine that other firefighters, paramedics, and construction workers were thinking the same thing as they tried to save lives after the deadly summer 2026 earthquakes in Venezuela, Colombia, and Indonesia or the disastrous floods in Nepal.
Some of these rescuers also had to recover human remains from the rubble. These moments of deep pain are surrounded by dust, toxic gases and cries for help. And this trauma takes its toll.
In industrial or nuclear disasters, extreme weather events, wildfires, volcanic eruptions, wars or terrorist attacks, first responders and affected communities can suffer significant effects on their physical and mental health both during rescue and recovery operations and for years afterward. Everyone is vulnerable to physical and mental harm, no matter how well trained they are.
My team’s research suggests that among these risks is post-traumatic stress disorder, which can cause your brain to age faster.
Post-traumatic stress disorder
Post-traumatic stress disorder, also known as PTSD, is a complex mental health disorder that can develop after experiencing or witnessing a traumatic event. Psychological trauma refers to the lasting emotional effects of direct or indirect exposure to life-threatening circumstances or violence.
PTSD can manifest as intrusive memories, avoidance behaviors, heightened alertness, sleep problems, and changes in mood and thinking. Anxiety and depression often occur along with PTSD.
About 23% of World Trade Center first responders have been diagnosed with PTSD. By comparison, it is estimated that about 6% of the general US population has suffered from PTSD in their lifetime.
When I talk to 9/11 rescuers, they describe their PTSD and cognitive difficulties as interrelated problems that continue to affect their lives to this day. Those traumatic memories remain vivid, and some rescuers continue to experience anxiety, depression, intrusive thoughts, trouble sleeping, and difficulty controlling their emotions.
Trauma accelerates brain aging
As they age, many 9/11 first responders have also noticed their memory, concentration, and mental acuity deteriorate. They are increasingly worried about losing their independence. Rather than presenting as separate conditions, physical illnesses, cognitive changes, and emotional distress often reinforce each other.
In another study, researchers on my team monitored the cognitive function of more than 5,000 World Trade Center rescuers without dementia between 2014 and 2022. Over about five years, 228 developed dementia before age 65. First responders with the most severe exposure to potentially neurotoxic dust and debris at ground zero had a substantially higher incidence of dementia than those with minimal exposure or who consistently used personal protective equipment, such as respirators. This relationship held after controlling for demographic, lifestyle, medical, and genetic factors.
Before I began studying the health effects of 9/11, I was researching workers exposed to neurotoxic metals and industrial pollution in northern Italy. Learning about the harmful toxins present in World Trade Center dust, I began to wonder if 9/11 rescuers might face similar long-term risks to their brains. That concern intensified when brain scans of both groups showed a similar increase in deposits of a protein linked to Alzheimer’s disease and cognitive decline called beta-amyloid.
Research by my team also revealed that the brains of men who participated in the 9/11 rescue efforts and who suffered from PTSD had MRI results that indicated older brains compared to those without PTSD.
In that 2025 study, we measured brain structures using MRI scans and an artificial intelligence model to estimate each participant’s brain age. The artificial intelligence model had been trained to predict a person’s chronological age from their overall brain structure, based on data from more than 11,500 brain MRIs of healthy people aged 5 to 95. We use the difference between a person’s predicted brain age and their actual age as a measure of accelerated brain aging.
We also observed that first responders with PTSD had brains that looked about three years older than their chronological age. In contrast, the estimated brain age of rescuers without PTSD roughly matched their actual chronological age. Each additional month they spent working at ground zero was associated with approximately four to five additional months of apparent brain aging, suggesting that time of exposure to the disaster played a key role in this aging process.
The experiences of first responders demonstrate that the effects of 9/11 remain a current health issue. These health consequences evolve as people age, and continue to require coordinated mental, cognitive, physical, and social support decades later.
Each anniversary of 9/11 brings back vivid memories of the tragedy, along with the same unease, frustration and pain of having been there. However, many of those who were on the front lines have told me that they feel pride and a sense of belonging knowing that they helped people who desperately needed it. Their service remains an enduring example of human solidarity in a time of crisis.
Honoring that legacy also means protecting those who come to our aid during an emergency. I believe that as a society, Americans have a responsibility to safeguard, protect and care for their health throughout their lives. They were there for America in one of its darkest moments; Americans must be there for them in the years to come.
