A Rampton patient told police he punched a male nurse in the face because he was being bullied, a court heard.
Darren Rettie was being escorted to the day room on the morning of September 29, last year, when he lashed out and stood over his victim, before staff arrived.
The blow caused a “whiplash-like” neck injury and soft tissue damage, said Daniel Pietryka, prosecuting.
Rettie, 29, admitted assault via his solicitor Jill Hawkins at Mansfield Magistrates Court, on Thursday.
Ms Hawkins said Rettie had been detained under the Mental Health Act since 2008 and had been at Rampton for two years, but there were plans to transfer him to a high-security hospital in Scotland, where he originally comes from.
She said his personality disorder had sparked the accusations of bullying, and his learning disability prevented him from understanding the consequences of his actions.
Rettie was ordered to pay the nurse £150 and £85 costs to the court.