Fetterman, who has struggled with the aftereffects of a stroke he suffered last May, checked himself in Wednesday night, it said.

“While John has experienced depression off and on throughout his life, it only became severe in recent weeks,” his chief of staff, Adam Jentleson, said in a statement.

Fetterman was evaluated Monday by the attending physician of Congress, Dr. Brian P. Monahan, who recommended inpatient care at Walter Reed, Jentleson said.

“John agreed, and he is receiving treatment on a voluntary basis,” Jentleson said. “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.”

Fetterman, 53, is in his first weeks as a U.S. senator after winning the seat held by now-retired Republican Pat Toomey in a hard-fought contest against GOP nominee Dr. Mehmet Oz. Fetterman, who was Pennsylvania’s lieutenant governor, defeated the celebrity heart surgeon by 5 percentage points, flipping a seat that was key to Democrats holding the Senate majority.

Fetterman’s wife, Gisele, said she was proud of Fetterman “for asking for help and getting the care he needs.”

“After what he’s been through in the past year, there’s probably no one who wanted to talk about his own health less than John,” she wrote on Twitter.

Fetterman overcame a stroke days before last May’s primary election and spent the last five months on the campaign trail recovering.

The stroke nearly killed him, he has said.

Fetterman underwent surgery to implant a pacemaker with a defibrillator to manage two heart conditions, atrial fibrillation and cardiomyopathy, and spent much of the summer recovering and off the campaign trail.

He refused to release his medical records or allow his doctors to answer reporters’ questions, as Oz made an issue of whether his opponent was honest about the effects of the stroke and whether Fetterman was fit to serve.

Fetterman’s campaign in October released a letter from a Pittsburgh-area physician who said he exhibited no effects on his “cognitive ability” or his ability to think and reason after the stroke, was recovering well and and “can work full duty in public office.”

He continues to suffer the aftereffects of the stroke, in particular auditory processing disorder, which can render someone unable to speak fluidly and quickly process spoken conversation into meaning. To manage it, Fetterman uses devices in conversations, meetings and congressional hearings that transcribe spoken words in real time.

Senators from both parties were supportive after Fetterman’s office announced the news, applauding him for getting help and acknowledging that he needed it.

Illinois Sen. Dick Durbin, the No. 2 Democrat in the Senate, learned about Fetterman’s hospitalization as he walked off the Senate floor after making a speech.

“I stand by John Fetterman and his family,” Durbin said. “This is a challenge, unimaginable challenge that he’s faced in life. He deserves the very best in professional care and I’m sure he’ll get it.”

He said he believed Fetterman would be “back in our ranks” and could serve a full six-year term.

The No. 2 Republican, Sen. John Thune of South Dakota, acknowledged he doesn’t know Fetterman very well yet but said he had senators were hoping and praying for his recovery.

“He’s been through a lot physically and mentally,” Thune said. “He’s got to take care of himself and his family. And I think everybody supports that.”

Last week, Fetterman stayed two days in George Washington University Hospital, checking himself in after becoming lightheaded. Fetterman’s office has said tests found no evidence of a new stroke or a seizure.