A judge has ordered a psychiatric report on a man who admitted carrying out an attack in Bury St Edmunds.
Andrew Ramsey, 27, who also uses the name Willoughby, was due to appear for trial at Ipswich Crown Court on Monday but changed his plea to guilty of assault inflicting grievous bodily harm.
The victim, Christopher Keel, was wounded in an incident in Prospect Row, Bury, last September.
The court heard that following the attack, Ramsey was taken to West Suffolk Hospital where doctors diagnosed he was suffering from drug-induced psychosis.
Ramsey, of Kipling Road, Ipswich, who has an alcohol problem, had previously been diagnosed as having what was described as a borderline personality disorder.
Judge John Holt ordered a psychiatric report before Ramsey is sentenced.