Two neurologists testified on Tuesday that the brain of Robert Bowers, the man who committed the synagogue massacre at the Tree of Life building in 2018, showed signs of schizophrenia.

Andrew Newberg, a neurologist at Thomas Jefferson University, testified that areas of Bowers’ brain displayed abnormalities on a PET scan taken in 2021. In particular, the scan showed that the left side of his brain was significantly more active than the right, an imbalance that Newberg says is consistent with a schizophrenia diagnosis.

However, Newberg said, a PET scan alone is not enough to secure a diagnosis. Clinical examination and other types of scans are necessary.

The defendant’s lawyers focused on his mental state through Day 2 of the second phase of the trial and called neurological experts to testify to Bowers’ mental disorders.

The defense hopes to convince the jury that the defendant was incapable of forming the requisite intent to commit a capital offense and is therefore not eligible for the death penalty. In opening statements on Monday for this phase of the trial, defense attorney Michael Burt said that psychiatric problems left the shooter “unable to make proper decisions based on his delusional beliefs.” He cited schizophrenia and epilepsy.

In addition to the asymmetry, Newberg testified that Bowers’ brain displayed increased metabolism in the areas of the brain that control emotion. Increased metabolism, Newberg said, can lead to delusions and abstract reasoning.

“There will not be the ability to process emotional or cognitive ideas as effectively,” Newberg said.

The scan showed decreased metabolism in areas that control stress responses, which can lead to a person becoming “over-reactive” to stresses in one’s environment. 

In cross-examination, U.S. Attorney Eric Olshan confirmed with Newberg that a PET scan is not conclusive, and that there is no recognized pattern for schizophrenia on a PET scan — only potential indicators.

Olshan got right to the point with his last question in an attempt to counter the defense’s arguments. 

“Is it your conclusion that a person with these abnormalities is incapable of killing another person?”

“That can’t be answered on the basis of a PET scan,” Newberg said.

The defendant’s lawyers aim to show that he was impaired by his mental disorders when he committed the killings. Earlier testimony related to the defense team’s assertion that Bowers suffers from epilepsy in addition to schizophrenia. Two neurologists did not find conclusive evidence to say that Bowers did or did not have epilepsy based on scans of his brain. However, Murray Solomon, a neuroradiologist who evaluated an MRI of his brain, testified that the preponderance of white matter lesions that showed up in the scan are potential indicators of schizophrenia, epilepsy or traumatic brain damage — something that Olshan challenged in a tense cross-examination.

Solomon had said he searched the white lesions on Google to ensure that schizophrenia was a potential cause. Olshan pressed him on it in an attempt to undermine his credibility.

The eligibility phase of the trial is expected to last one to two weeks, and if the jury decides unanimously that the defendant is eligible for the death penalty, a third phase will follow to determine sentencing.

This story is part of ongoing coverage of the Pittsburgh synagogue shooting trial by the Pittsburgh Jewish Chronicle and the Pittsburgh Union Progress in a collaboration supported by funding from the Pittsburgh Media Partnership.

Harrison, a rising senior at Denison University, is a Union Progress summer intern. Email him at

Harrison Hamm

Harrison, a rising senior at Denison University, is a Union Progress summer intern. Email him at