Fentanyl "Amnesia" Continues To Perplex Health Officials

By Paul Gaita 03/27/18

New cases of the mysterious syndrome have renewed efforts to determine fentanyl's exact impact. 

confused man with his hands on his head

Since 2012, reports from the New England area have noted a small but steady increase in the number of patients reporting a form of amnesia as well as damage to an area of the brain that oversees memory.

More than 14 such cases were documented by the end of the 2016, and were initially attributed to fentanyl overdose due to the patients' medical history, and the rise in use and subsequent overdose deaths related to the synthetic painkiller.

Now, as a new report reveals that four more cases have been confirmed since 2017, scientists are attempting to determine exactly what role fentanyl use plays in these incidents, as well as which other factors may have had a hand in the rise of this mysterious syndrome.

The report, published in the New England Journal of Medicine's March 2018 edition, describes the condition as "acute anterograde amnestic syndrome," which presented itself as an inability to form new memories that could last months or even longer. Orientation and attention also appeared to be affected by the syndrome, which on a brain scan, displayed a pattern of damage to the hippocampi, twin structures located near the center of the brain that are believed to play a role in spatial navigation and turning short-term experiences to long-term memories.

According to a feature on PBS, the first known case was reported in 2012 by a Boston-area hospital treating an individual who may have suffered a heroin overdose.

Since then, 14 more cases in New England and another in West Virginia have been identified, of which 13 were reported to have a history of opioid use, though none were tested for fentanyl. The Journal of Medicine study reviews four additional cases documented in 2017, which concerned individuals between the ages of 28 to 37 who showed signs of the syndrome.

In all four cases, the individuals tested positive for fentanyl, which was also the only drug present in the systems of two subjects. These tests appeared to support diagnoses made in 2016, which linked the side effects of the syndrome to fentanyl use due to its increased presence among drug users.

At that time, the evidence to support the theory was circumstantial at best, as toxicology reports did not screen for the synthetic opioid. 

As PBS reports, the Massachusetts Department of Health began informing health professionals to request advanced toxicology screens for any patients that shows signs of the syndrome.

The increase in lab tests for the drug led to the revelation of the four new cases and renewed efforts to determine exactly how fentanyl impacted these individuals. 

So far, the report authors have drawn a link between laboratory tests in rats which showed severe damage to neurons in the hippocampus after being administered fentanyl and instances of excitotoxicity, which occurs when neurons in the brain receive excessive stimulation. Oxygen depletion to the brain during overdose also may play a role in the development of the syndrome.

The authors also acknowledge the possibility that genetics may have impacted the individuals diagnosed with the syndrome, since the great majority of overdose victims do not show any signs.

They conclude their report by noting that expanded screening may prove crucial in determining the exact link between fentanyl and the syndrome. 

"You have scientific plausibility and consistency [in these cases]," said Dr. Alfred DeMaria, state epidemiologist for Massachusetts. "What we don't have is proof of cause and effect."

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Paul Gaita lives in Los Angeles. He has contributed to the Los Angeles Times, Variety, LA Weekly, Amazon.com and The Los Angeles Beat, among many other publications and websites.