James Robert Derrett, 43, appeared in the Dunedin District Court yesterday after earlier pleading guilty to wounding with reckless disregard.
The court heard that on June 27, the defendant and his brother were walking home when they got into an argument about neither of them having any cannabis.
The pair grappled and the victim was dragged to the ground by Derrett, who then sat on top of the man and delivered at least 20 punches to his head.
The victim fainted while talking to police and was bleeding from his ears and head after the attack.
He still felt the effects of the offending every day, and struggled with the emotional and psychological impacts, he said.
He suffered a significant concussion and required shoulder surgery, which affected his ability to work.
A psychological assessment found Derrett was ‘‘disinhibited due to psychotic symptoms’’ at the time.
Judge Emma Parsons accepted the defendant had a ‘‘complicated mental health history’’, which contributed to the attack.
The judge sentenced Derrett to three months’ community detention, with a 7pm-7am curfew.
