TUESDAY, Aug. 30, 2016 (HealthDay News) -- The 9/11 attack on the World Trade Center continues to the ravage the minds of those who responded to the Twin Towers collapse, new research shows.
Post-traumatic stress disorder (PTSD) experienced by many rescuers and other first responders now appears linked to mental decline and dementia, the study authors found.
"People with PTSD, regardless from where they get it, are more likely to have cognitive impairment earlier," said lead researcher Sean Clouston, referring to memory and thinking abnormalities.
About one-fifth of the World Trade Center responders developed PTSD, according to background notes with the study.
"World Trade Center PTSD is associated with potential cognitive impairment, and cognitive impairment is a risk factor for dementia," said Clouston, an assistant professor of family population and preventive medicine at Stony Brook University in New York.
After examining more than 800 first responders more than a decade after the 2001 attacks, Clouston's team concluded the risk for mental decline is twice as high for those who developed PTSD compared to those without the severe anxiety disorder. And for those reliving the scene mentally without a PTSD diagnosis, the risk is three times as high, Clouston said.
Together, PTSD and mental impairment create a double whammy that threatens someone's ability to handle their medicines, keep appointments and otherwise manage their day-to-day affairs, he explained.
The 818 first responders included in the study were age 53, on average, and all had diagnosed PTSD, flashbacks or nightmares. Tests of reasoning, concentration, problem-solving and memory were done in 2014 and 2015, along with psychological evaluations.
About 13 percent showed signs of memory and decision-making problems, and about 1 percent had early signs of possible dementia, the researchers found.
These findings replicate a similar finding among military veterans, Clouston said. The main difference here is that the 9/11 responders did not have head injuries, but many of the veterans did. In that way, the risk of mental decline can be separated from head injury, thus making the connection with PTSD stronger, Clouston said.
In 2002, the U.S. Centers for Disease Control and Prevention enrolled 33,000 first responders in a World Trade Center Health Program.
If the latest findings are representative of that larger group, Clouston said, they suggest as many as 4,000 or 5,000 responders may be developing mental impairment and hundreds may be at risk for early dementia..
Given the average age of 53 in the current study, "these numbers are staggering," Clouston said.
Why PTSD is connected to mental decline isn't clear, nor does the study establish a direct cause-and-effect relationship.
Also, whether treating PTSD lowers the risk isn't known, Clouston said. The researchers plan to follow these responders to see whether their mental decline worsens or if dementia develops.
People with PTSD and signs of mental decline don't necessarily develop full-blown dementia, Clouston said. Moreover, most people can cope with their impairment in memory and decision-making, and many don't even know they have it, he added.
The report was published online Aug. 29 in the journal Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring.
Overall, Clouston's team found that responders with PTSD and mental decline had lower education, were likely to have jobs such as construction or utility workers, were older and smoked, compared with those without mental decline.
Declines in thinking and memory associated with PTSD remained even after the researchers accounted for education, occupation, trauma severity, smoking, hazardous drinking and various health conditions.
Heather Snyder, senior director of medical and scientific operations at the Alzheimer's Association, advises people who have concerns about their memory to speak with their doctor.
"This study allow us to further tease out the link between PSTD and cognitive decline separate for people who may have head injury," said Snyder.
"We really don't know how serious the risk is," she said. "There's a lot we don't understand about how and why PTSD may be impacting the brain and its overall function."
For more on PTSD, visit the U.S. National Institute of Mental Health.