A son described as recluse, who stabbed his mother to death, had his murder trial halted after a plea of diminished responsibility was accepted.
Jamie Fort, 20, of Castle Bromwich, West Midlands, had admitted the manslaughter of his mother Patricia but denied murder.
Jurors at Birmingham Crown Court were discharged after his plea was accepted.
The court was told Fort stabbed his mother more than 80 times in the living room of their home in July 2008.
Fort, of Lanchester Way, then dialled the emergency services. Mrs Fort's husband and daughter were asleep upstairs at the time.
Psychiatrists involved in the case agreed Fort was suffering from an abnormality of the mind at the time of the offence.
He will be sentenced at a later date.