Hostel resident Christopher Knight was so agitated about "being woken up for six weeks" he threatened staff with a knife, a court heard.
Knight caused a rumpus at the Salvation Army's Logos House premises in Wade Street, telling people: "Police will have to shoot me because I'm not going to give up my knife."
It transpired Knight had not taken mood stabilising medication at the time.
And Bristol Crown Court heard coronavirus lockdown meant a medical examination had been cancelled, and he had since been diagnosed with and medicated for ADHD.
Knight, 26, of Snowberry Walk in St George, pleaded guilty to possessing a knife and affray on July 2.
Judge Michael Longman handed him 12 months' jail, suspended for two years.
He said Knight had been liked at the hostel, and the incident had been bizarre.
The judge told him: "The prospect of rehabilitation weighs in favour of suspension.
"I am taking a calculated risk."
Knight told the judge: "I'm fully committed to prove myself to the court and my family.
"Thank you very much your honour, I will not let you down."
Neil Treharne, prosecuting, said Knight was abusive in the facility's canteen, shouting at residents.
When a staff member asked him to calm down he was abusive to him, saying he had been woken up for six weeks.
The court heard he then exited the canteen, swung a golf umbrella and said: "The first person to come down here is going to get hit."
Mr Treharne said that, after throwing a chair and a sign towards a door, Knight shook his right arm and a kitchen knife appeared which he brandished - saying police would have to shoot him to take it off him.
He then returned to the canteen with his knife at shoulder height, and threw another chair.
Mr Treharne said: "All the staff were concerned.
"Fortunately nobody was injured.
"The defendant did cut his own hand."
Though Knight left scene he returned later, threatened to stab a member of staff and police were called in.
Officers found him in Pennywell Road with a knife in his rucksack and he was arrested.
He told police: "I put the knife in my bag because I'm homeless, I got kicked out of there."
Matthew Comer, defending, said his client was liked at the hostel, which made the incident all the more bizarre.
Mr Comer said: "He was not taking medication for ADHD.
"He was using Class A drugs.
"It was having a detrimental effect on his mental health."
