He was mentally affected when he committed the crime.
The Court heard he first became aware of the symptoms of mental illness after drinking some custom medicine for protection against black magic.
His relatives arranged for him to travel to Honiara so they can care for him.
He was staying with his Town Ground relatives when he attacked the deceased with two knives.
He inflicted a total of twelve stab wounds to his body which resulted in death almost immediately.
Chief Justice Sir Albert Palmer says there is a high risk the accused might commit the same offence again because no medical treatment has been prescribed for him.
He sentenced him to life imprisonment but says depending on how successful any medical treatment might be and subject to the Commissioner of the Correctional service, he may be considered for parole.