Fetterman's staff couldn't tell if his detached behavior was from his stroke or his depression: report

On Wednesday, Sen. John Fetterman (D-PA) checked himself into Walter Reed National Military Medical Center to "receive treatment for clinical depression," according to a statement from his chief of staff, Adam Jentleson.

"While John has experienced depression off and on throughout his life, it only became severe in recent weeks," Jentleson said.

An aide to Fetterman told NBC News that the Democratic senator will likely remain in inpatient care for clinical depression for "a few weeks," as doctors try to figure out what medications will help him most.

"Based on conversations the aide has had with the senator about the challenges he's faced post-stroke, the aide described Fetterman's struggle adjusting to his new reality and said the senator has wrestled with questions about his self-worth," NBC News reported.

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In a series of posts to Twitter, NBC's Dasha Burns -- who was widely criticized by podcasters and other journalists for questioning whether Fetterman was healthy enough to do his job as a senator in the wake of the stroke he suffered during his campaign -- cited a senior aide to Fetterman who told her that "it’s been difficult to distinguish the stroke from the depression – saying it’s hard to tell at times if Fetterman is 'not hearing you, or is he sort of crippled by his depression and social anxiety.'"

"A senior aide tells me both the staff and Fetterman himself were taken by surprise by the severe onset of depression," Burns reported. "The aide also says this hasn't compromised his ability to do the job going forward, and he will be back to work once he has taken care of his mental health."

Fetterman suffered a stroke last year before he won the Pennsylvania Senate race in a highly competitive contest against Mehmet Oz. He was hospitalized earlier this month after he felt lightheaded but tests ruled out another stroke.

“On Monday, John was evaluated by Dr. Brian P. Monahan, the Attending Physician of the United States Congress. Yesterday, Dr. Monahan recommended inpatient care at Walter Reed. John agreed, and he is receiving treatment on a voluntary basis," Jentleson said in a statement Thursday. “After examining John, the doctors at Walter Reed told us that John is getting the care he needs, and will soon be back to himself.”