Pathologists to Search Stephen Paddock’s Brain for Clues to Mass Shooting

Neuropathology experts warn that finding proof of dementia or trauma in the mass shooter's brain isn't likely to provide a definitive reason for his behavior.

But even if scientists find clear evidence in Paddock’s brain of a neurodegenerative disease like Alzheimer’s or a brain injury like chronic traumatic encephalopathy (CTE), will that help to explain why a reclusive gambler with no criminal record or extremist ties would open fire on a crowd of innocent people?

Dr. Clayton Wiley is a professor of pathology and director of neuropathology at the University of Pittsburgh Medical Center. Although he’s not involved in Paddock’s case, he regularly conducts brain autopsies for both academic research and for the Pittsburgh medical examiner’s office.

In an interview with Seeker, Wiley strongly disagreed with the notion that physical evidence of brain disease or trauma can explain or excuse aberrant behavior. He explained that the tools of a forensic pathologist are relatively “crude,” only able to detect clear evidence of a neurodegenerative disease like brain atrophy, or the telltale signs of CTE like tau protein deposits. But that’s where the pathologist’s expertise ends.

“Can a pathologist look at a brain and say that these changes are such that this person would commit mass murder, or this person would commit suicide? The answer is no,” Wiley said. “Unequivocally, no.”

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Paddock’s brain will be sliced up and analyzed by Dr. Hannes Vogel at Stanford, who said in an interview with The New York Times that he would be paying particularly close attention to the frontal and temporal lobes. Paddock was 64 years old, and hereditary forms of frontotemporal dementia (FTD) can strike when an individual is still in their fifties. Symptoms of FTD include marked personality changes and impaired decision-making.

Vogel acknowledged that it’s “unlikely” that a person with FTD could carry out the meticulous planning necessary to pull off such a deadly surprise attack, but that he “wouldn’t want to leave any stone unturned.”

The examination of Paddock’s brain comes at an interesting time in legal dynamics of brain injuries. Earlier this year, researchers at Boston University confirmed that ex-professional football player and convicted murderer Aaron Hernandez suffered from Stage 3 CTE, the result of repeated hits to the head. CTE can only be diagnosed by an autopsy, but if juries had known about Hernandez’s condition, which is marked by aggressiveness, impulsivity, and explosiveness, it may have allowed him to plead not guilty by insanity.

Hernandez hung himself in his jail cell after being sentenced to 33 years in prison for the murder of his friend, Odin Lloyd. However, Hernandez’s post-mortem diagnosis of CTE could be used to defend his estate against civil charges. A similar defense could be used in civil suits against Paddock and his estate, if he was found to have a brain disorder that rendered him unaccountable for his actions.

The problem, explained Wiley, is that pathological evidence of a damaged or impaired brain doesn’t translate directly to certain outward behaviors. He used Alzheimer’s disease as an example.

“We can identify people who have neurological changes associated with Alzheimer’s disease who are not demented,” said Wiley. “They do not have clinical Alzheimer’s disease. And yet, if you looked at the autopsy report on their brain, it would say either ‘Alzheimer’s changes’ or ‘Alzheimer’s disease.’”

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There’s an even weaker causal relationship between structural abnormalities in the brain and psychological conditions like schizophrenia and psychopathy, which are often associated with mass murderers.

Dr. Eyas Hattab, professor and chair of the Department of Pathology and Laboratory Medicine at the University of Louisville, told Seeker that no piece of evidence found during a post-mortem brain examination can reliably be cited as the cause of antisocial or psychotic behavior. That’s beyond the limits of science in 2017.

Hattab said that it would have been much more informative to run tests on Paddock’s brain when he was still alive. Paddock killed himself after his shooting rampage.

“With a living person, we’re able to administer functional tests — fMRI scans, for example — that are far more informative than any structural abnormalities uncovered in an autopsy,” said Hattab. “Those scans could show us if there are any behavior-altering chemicals in the brain, or active regions in the brain that have been associated with antisocial behavior.”

As for this week’s high-profile examination of Paddock’s brain, UPMC’S Wiley is bracing for the usual unscientific media commentaries linking the brain and behavior. At the end of the day, he’s concerned that neuropathologists are being asked to perform a role that exceeds their understanding.

“People will come away with the interpretation that somehow we have this magical skill of explaining how people behave by looking at tissue from their brain,” he said, “and that’s not possible.”

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