It all started with Max Meehan, who was taken to the hospital after his behavior freaked out his family: his memory had suddenly vanished.
Since 2012, doctors in Massachusetts have observed a most unusual kind of patient. There are only 14 cases were recorded in history to have the same symptoms and effects.
“The kid was amnestic,” neurologist Yuval Zabar says of the then-23-year-old, and what Zabar found when he reviewed an MRI scan of Meehan’s brain essentially freaked him out.
Zabar ordered an MRI scan, which highlights brain areas that have been damaged by a lack of oxygen, or “ischemia.” Inside Max’s skull, he could make out the gray, jello-like silhouettes of various brain regions. But clustered near the center were two glowing orbs of white.
The spots were perfectly localized, on each side of the brain, to the hippocampus, the seahorse-shaped region that encodes new memories. In his 20 years of treating patients with neurological problems, Zabar said, he had never seen anything like it.
In Meehan’s case, he shot up heroin and collapsed before waking to a seeming inability to form new memories, leaving him in a state that forced him to drop out of college and made it difficult to hold a job.
Some experts think it’s a genetic sensitivity to something in the drugs. Others think it could be a gradual weakening of hippocampal neurons over time, caused by the respiratory depression of strong opioid use. And others posit that it’s a side effect of an overdose or prolonged slow breathing.
“I would fully expect this to happen with respiratory depression or respiratory arrest from opioids,” said Gary Franklin, a research professor in neurology at the University of Washington. “If they think that something extremely special is going on here, like one of these drugs did something very targeted, I don’t think so.”
Memory improvements came slowly over two years. “The only thing that seems to parallel” the condition—which has been named CHIAS, for complete hippocampal ischemic amnestic syndrome—”is fentanyl use,” says another Massachusetts neurologist. Among the many varied theories: that there was a toxin in the drugs ingested, or that persistent fentanyl use results in severe respiratory issues that may deprive those parts of the brain of oxygen. For now, state public health officials are pushing the mystery forward by branding CHIAS a “reportable disease,” meaning the state will have to be alerted to any new cases.