A Rampton patient who punched a female member of staff as she walked past him could not explain why he did it, a court heard.
Simon Taylor swung out and hit the woman on her right ear as he was walking past the dining room, at 1pm on December 22.
She was left with a painful and swollen ear, but no permanent injuries were sustained, said prosecutor Robert Carr.
The court heard Taylor had been convicted of sexual assault in 2016.
Jamie Nelson, mitigating, said: “He hasn’t been able to offer any explanation as to why he committed the offence.
“He will be remaining there for the foreseeable future.”
Taylor, 42, admitted common assault, via his solicitor, at Mansfield Magistrates Court on Friday.
Magistrates ordered him to pay £100 compensation to the woman, at the rate of £10 per week from his benefits. No costs were awarded.