A DRUG-using festival goer attacked a stallholder after violent scenes at a midnight movie screening made him believe he was being hunted by Nazi assassins.
Samuel Billyard, 23, had been taking drugs at the three-day event at a farm near Tiverton and had been seen acting strangely before he launched the unprovoked assault.
Victim Hannah Burgess, who went to the event to sell her hand-made artworks, spent two days in hospital with a broken jaw after being smashed across the face with a piece of wood.
She was walking through woodland to watch a midnight movie screening at the party at Coombe Farm, Cove, when she was attacked without warning, Exeter Crown Court was told.
Billyard, of Vicarage Hill, Kingsteignton, who is now being treated at the Amber Project in Chawleigh, admitted causing grievous bodily harm and having an offensive weapon.
He was jailed for 12 months, suspended for two years and ordered to receive treatment at the Amber Project.
He has already spent 15 months at the Cygnet Hospital at Kewstoke, Weston-super-Mare, being treated for psychosis after being sectioned the day after the attack in July last year.
Recorder Mr Kevin de Haan QC, told him: "You are a young man of considerable intelligence who has a great deal of insight into what you did and appreciate it was an extremely serious, unprovoked attack on a young woman.
"It has left her with a degree of permanent injury. I rather suspect you hate yourself for this and have gone through a great deal of soul searching over it."
Bathsheba Cassel, prosecuting, said Billyard was a guest at the weekend party in July 2011.
Guests had already noticed his strange behaviour, which included wearing all his clothes back to front and rolling in the grass while holding a large stick.
"Miss Burgess made an impact statement saying it affected her mentally and she suffered flashbacks and nightmares and felt depressed, vulnerable, agoraphobic and afraid of the dark," Miss Cassel said.
"He said he attacked the victim because he thought she was going to kill him on behalf of Hitler."
Terry Holder, defending, said Billyard had insight into his own mental health problems and was keen to receive more treatment.