Pennsylvania Sen. John Fetterman checked himself into Walter Reed National Military Medical Center on Wednesday night to "receive treatment for clinical depression," his spokepserson said Thursday.

"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. “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.”

"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," Jentleson added.

Fetterman, 53, suffered a stroke just days before winning the Pennsylvania Democratic primary for U.S. Senate last year, and recovered while on the campaign trail against Republican Mehmet Oz. Fetterman handily defeated Oz in last year's midterms to flip a seat held by retiring Republican Pat Toomey, helping the Democrats expand their Senate majority. 

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

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.

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.

"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," his wife, Gisele Barreto Fetterman, wrote in a Twitter post. "I’m so proud of him for asking for help and getting the care he needs."

"This is a difficult time for our family, so please respect our privacy. For us, the kids come first," the former Second Lady of Pennsylvania wrote in a follow-up post. "Take care of yourselves. Hold your loved ones close, you are not alone."

The announcement prompted an outpouring of support, including many of Fetterman's fellow lawmakers, who hailed the Pennsylvania Senator for his bravery in getting help.

The White House on Friday applauded Fetterman for getting the help he needs and bringing awareness to mental health struggles.

"Millions of Americans go untreated with depression every day," White House chief spokesperson Karine Jean-Pierre said at a briefing Friday. "Sen. Fetterman did the right thing and brave thing ... by getting the help that he definitely needs."

"As the president and first lady shared this morning, they are thinking about John, Gisele and their entire Fetterman family today, and they are grateful to Sen. Fetterman to being an example," she added.

Jean-Pierre also touted the efforts to fund mental health programs that President Biden called for in his State of the Union address earlier this month.

"Millions of Americans struggle with their mental health," wrote fellow Pennsylvania Sen. Bob Casey. "I am proud of @SenFettermanPA for getting the help he needs and for publicly acknowledging his challenges to break down the stigma for others. Terese and I are sending our prayers to John, Gisele, and the Fetterman family."

Majority Leader Chuck Schumer, D-N.Y., wrote that he is "happy to hear" Fetterman "is getting the help he needs and deserves."

"Millions of Americans, like John, struggle with depression each day. I am looking forward to seeing him return to the Senate soon," he added. "Sending love and support to John, Gisele, and their family."

"I didn’t realize @JohnFetterman was struggling w/ depression," wrote Sen. Kyrsten Sinema, I-Ariz., who shared a Harvard Business Review article about how to support someone experiencing a mental health crisis.

"Many who face depression do so w/o those around them knowing. We can all help each other by learning to be a mental health ally," she added. "If you’re struggling w/ depression, you can call 988 to get help."

"Senator Fetterman showed only strength with his decision," New York Rep. Yvette Clarke wrote on Twitter. "The mental health crisis confronting America affects people from all walks of life — we can beat it together. Praying for John, and so very proud of him for getting the treatment he needs."

"In the short time I’ve worked with John Fetterman, I’ve been struck by his resilience and heart," Minnesota Sen. Tina Smith wrote on Twitter. "John is doing exactly what he should do, which is seek help. Seeking help when you need it is a sign of strength, not weakness, something that John is demonstrating for all of us."

"Thinking about Senator Fetterman today," wrote California Rep. Adam Schiff. "Glad he is getting the support he needs at Walter Reed. Proud he is being open about his struggle with depression and hoping it encourages others to seek help who need it. Stay strong, John. We are with you."

"The importance of our mental health cannot be overstated," New York Attorney General Letitia James wrote on Twitter, commending Fetterman for his "bravery to seek treatment for his own mental health challenges."

"My thoughts are with you and your family, Senator," James added.

"Sending fierce love and solidarity to Senator Fetterman and the good people of Pennsylvania," Maryland Rep. Jamie Raskin wrote on Twitter. "Sending every wish for full recovery and good health."

"It’s okay not to be okay," said Jerome Adams, who served as U.S. Surgeon General under former President Donald Trump. "Even if you’re a United States Senator. If you’re feeling severely depressed / in crisis, call 988. Help is just a phone call away."

The Associated Press contributed to this report.