Neurologists are looking into a series of cases that might indicate that opioids are the cause behind strange cases of amnesia. The pattern emerged about a year ago when three out of four amnesia patients checked by a Massachusetts neurologist tested positive for opioids.
An MRI scan conducted by the neurologist led them to witness an unusual specter. All four of the patients experienced the same issue: the hippocampi was receiving little or no blood, two slivers of tissue deep in brain, one on the right and one left, involved in memory.
The damage in the patients' brains was specifically to the hippocampus neurons. The impairment of the hippocampi left them incapable of forming new memories. Since this is opposed to how opioids generally work, it raises the question whether this is a novel designer drug's new effect or instead a rare undiscovered effect from existing opioids?
The four cases were written up by the neurologist, Jed Barash, who then worked at Lahey Hospital and Medical Center. After promptly reporting them to the Massachusetts Department of Public Health, state doctors were prompted to riffle through their patient records in search of other amnesia cases who shared an opioid use history.
The findings showed a total of 14 patients who shared similar symptoms in Massachusetts in the past few years. Follow up proved useful on only three cases, two of which continued to have shrunken hippocampi while only one recovered fully.
CDC's Morbidity and Mortality Weekly Report published the findings that week. An epidemiologist with the Massachusetts Department of Public Health, Alfred DeMaria, Jr., said, "We wanted to put it to wider attention".
Other brain experts were surprised by the blood flow pattern in the brain, too. Neuroscientist Michael Bennett, from Albert Einstein College of Medicine said, "I don't think anybody really knows how the vasculature can lead to reduced blood flow in the hippocampus, rather specifically and bilaterally."
Stimulants like meth cause spasms in blood vessels where the rear and front of the brain bear the damage's brunt. Psychiatrist Thomas Kosten at Baylor stated, "Those areas are most affected because they're the very end of the distribution of the arteries."
The hypothesis of Kosten is that in addition to the opioid effect another drug was working as the stimulant. Patients, in several cases, reported the use of amphetamines, cocaine, or benzodiazepines alongside the opioids.
With the rise in the opioid crisis, scientists are yet to learn far more regarding how opioids affect the brain.
