Post-traumatic stress disorder linked to the September 11 terrorist attacks may be speeding up brain aging in the first responders who worked at Ground Zero, according to research led by Roberto Lucchini, a professor of Occupational and Environmental Health Sciences at Florida International University.
Lucchini, who has worked with 9/11 first responders as an occupational health physician, said hundreds of them have told him they still remember exactly how they felt during the attacks 25 years on, describing not being able to think, see or smell anything and focusing only on digging through debris to reach survivors.
Nearly 3,000 people died in the 2001 attacks on the World Trade Center. A memorial marking the 25th anniversary was held on September 11, 2026, with people gathering by the site's reflecting pool.
PTSD rates among 9/11 responders
About 23 percent of World Trade Center responders have been diagnosed with PTSD, compared with roughly six percent of the general US population estimated to have had the condition over their lifetime, Lucchini said.
PTSD is a mental health condition that can develop after someone experiences or witnesses a traumatic event. It can involve intrusive memories, avoidance, heightened alertness, sleep problems and changes in mood and thinking, and often occurs alongside anxiety and depression.
Lucchini said first responders he has spoken to describe their PTSD and cognitive difficulties as linked problems that continue to affect their lives, with many still experiencing anxiety, depression, intrusive thoughts, sleep problems and difficulty controlling their emotions.
Dementia diagnoses linked to toxic dust exposure
Lucchini's team monitored the cognitive function of more than 5,000 World Trade Center first responders without dementia between 2014 and 2022. Over roughly five years, 228 of them developed dementia before the age of 65.
Those 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 wore protective equipment such as respirators, the research found. The link held even after accounting for demographic, lifestyle, medical and genetic factors.
Before turning to 9/11 research, Lucchini studied workers exposed to neurotoxic metals and industrial pollution in northern Italy. He said his concern about long-term brain risks for 9/11 responders grew after brain scans of both groups showed a similar increase in deposits of beta-amyloid, a protein linked to Alzheimer's disease and cognitive decline.
Brains appearing three years older
A separate 2025 study by Lucchini's team used MRI scans and an artificial intelligence model to estimate the brain age of male 9/11 responders. The AI model had been trained to predict a person's chronological age from brain structure using data from more than 11,500 MRI scans of healthy people aged five to 95.
Researchers used the gap between a person's predicted brain age and their actual age as a measure of accelerated aging. They found that responders with PTSD had brains that appeared about three years older than their chronological age, while the estimated brain age of responders without PTSD roughly matched their actual age.
Each additional month a first responder spent working at Ground Zero was associated with roughly four to five additional months of apparent brain aging, the study found, suggesting the length of exposure to the disaster site played a key role in the process.
Ongoing support for first responders
Lucchini said the experiences of 9/11 first responders show the health effects of the attacks remain an ongoing issue that evolves as survivors age, requiring coordinated mental, cognitive, physical and social support decades later.
He said many first responders still feel restlessness, frustration and pain around each anniversary, but also pride and a sense of belonging from having helped people in desperate need. Lucchini drew a parallel with responders working after the 2026 earthquakes in Venezuela, Colombia and Indonesia and the floods in Nepal, saying he could easily imagine firefighters, paramedics and construction workers there having similar experiences while trying to save lives and recover human remains.
