PTSD Triggering Early Cognitive Trouble in 9/11 Responders?

Megan Brooks

September 01, 2016

Fifteen years after the attacks on the World Trade Center (WTC) on September 11, 2001, some first responders who are now in their 50s are experiencing early cognitive impairment, possibly triggered by posttraumatic stress disorder (PTSD), a new study suggests.

"A large number of WTC responders, who are well educated and were assessed at midlife, had scores indicative of milder forms of cognitive impairment when using an objective measure of cognitive functioning," lead investigator Sean Clouston, PhD, assistant professor, Program in Public Health at Stony Brook University, New York, told Medscape Medical News.

Notably, he said that responders with PTSD – especially those with reexperiencing symptoms – were more likely to screen positive for cognitive impairment and dementia.

Dr Sean Clouston

The findings linking PTSD to increased cognitive decline and dementia replicate associations seen in previous studies of veterans in a civilian population without head trauma, the authors note.

The study was published online August 19 in Alzheimer's and Dementia: Diagnosis, Assessment and Disease Monitoring.

"Staggering" Numbers

During the WTC attacks, first responders suffered an array of traumatic and toxic exposures. One fifth of responders subsequently developed PTSD.

In July 2002, federal health officials started a monitoring and treatment program for WTC responders. Since then, more than 33,000 responders have enrolled. Stony Brook University runs the second largest program, monitoring more than 8000 responders living on Long Island, New York.

For this study, Dr Clouston and colleagues examined the association of PTSD and major depressive disorder (MDD) with cognitive impairment and dementia in a sample of 813 civilian WTC responders without head injury. The average age of the patients was 52.8 years.

From January 2014 to April 2015, trained clinicians administered the Montreal Cognitive Assessment, which consists of multiple short-form tests of reasoning, concentration, problem solving, and memory. They used a "relatively conservative" cutoff score of <23 to indicate cognitive impairment and a score of <18 to suggest possible dementia.

A total of 104 responders (12.8%) screened positive for cognitive impairment, of whom 10 (1.2%) had probable dementia. If representative of the prevalence of cognitive impairment in the general responder cohort of roughly 33,000, this may translate into 3740 to 5300 responders with cognitive impairment, and 240 to 810 with dementia, the investigators calculate. "These numbers are staggering, considering that the average age of responders was 53 during this study," they write.

Responders with cognitive impairment had lower education, non–law enforcement occupations (such as utility or construction workers), were of older age, and were more apt to be current smokers than their peers without cognitive impairment.

Current, but not remitted, PTSD and MDD were associated with about a twofold increase in cognitive impairment. Longitudinal analyses showed "growth" in a number of symptom domains, including avoidance, numbing, hyperarousal, and depressive symptoms among responders who later screened positive for cognitive impairment. "Such growth may indicate early manifestations of cognitive impairment," the investigators write.

"Strikingly," they say, reexperiencing symptoms – a major component of PTSD – was consistently predictive of cognitive impairment 14 years later (adjusted relative risk 2.88; 95% confidence interval, 1.35 - 6.22).

"Clinicians caring for traumatized populations may want to be aware of cognitive impairment when creating treatment regimens for PTSD (and the reverse)," Dr Clouston told Medscape Medical News.

"Troubling" New Findings

In an interview with Medscape Medical News, Heather Snyder, PhD, senior director of medical and scientific operations at the Alzheimer's Association, said, "It's really important to understand all of the pieces of the puzzle that may cause someone to go on to develop cognitive decline [and] dementia that impairs their function and ability to live independently.

"We've seen studies over the last several years looking at the connection between PTSD and later-life risk of cognitive impairment and/or dementia, and this study adds to that body [in] a different population, a civilian population," Dr Snyder said.

It is not entirely clear why PTSD might lead to cognitive impairment, Dr Snyder said. "There are a lot of questions," and more research is needed, she added.

In a prepared statement, Maria Carrillo, PhD, chief science officer for the Alzheimer's Association, said, "The silver lining in these troubling new findings is that they will help us better understand the relationship between PTSD, cognition, and dementia. This is crucial so that we can provide better care for all individuals who experience PTSD."

The study had no commercial funding. The authors have disclosed no relevant financial relationships.

Alzheimers Dement. Published online August 19, 2016. Full text

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