The Pennsylvania US senator John Fetterman checked into hospital on Wednesday to receive treatment for clinical depression, his chief of staff said.

The news came a week after the Democrat, who suffered a stroke while campaigning last year, was hospitalised after feeling light-headed. Fetterman is a rising star among Democrats.

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

Last November, the 53-year-old former mayor of Braddock and state lieutenant governor flipped a Republican-held Senate seat, defeating the Trump-endorsed celebrity doctor Mehmet Oz to give his party control of the chamber by 51 seats to 49.

Fetterman suffered a serious stroke during the campaign, prompting Republicans to claim he was not fit to take office.

In his victory speech, Fetterman referred to the stroke when he said he campaigned for “anyone that ever got knocked down that got back up”.

Last Wednesday, Fetterman was taken to hospital in Washington DC after feeling light-headed at a Democratic event.

He was released last Friday. A spokesperson said then: “In addition to the CT, CTA, and MRI tests ruling out a stroke, his EEG test results came back normal, with no evidence of seizures. John is looking forward to spending some time with his family and returning to the Senate on Monday.”

In his statement on Thursday, Jentleson said: “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” in Bethesda, Maryland.

“John agreed, and he is receiving treatment on a voluntary basis. After examining John, the doctors at Walter Reed told us John is getting the care he needs, and will soon be back to himself.”

Among well-wishers, the former Obama adviser Tommy Vietor said Fetterman was “incredibly brave … to talk about his mental health challenges publicly, especially knowing that people will try to exploit it for political purposes.

“But his decision to come forward will undoubtedly help encourage others to seek help.”