Teenager stabbed mother 80 times
Jamie Fort stabbed Patricia Fort, 57, more than 80 times in their living-room in July 2008 as his father and sister slept upstairs, Birmingham Crown Court heard.
Prosecutor Christopher Hotten, QC, told the jury Fort, who was 18 at the time, launched the "sustained assault" on his mother just after 3am on 28 July, 2008, as she slept in the lounge.
He then called emergency services from the house in Castle Bromwich, Birmingham, saying he had killed her.
The court heard she had suffered 35 separate wounds and groups of wounds - some including several stabs or punctures - to her face, neck, chest and abdomen, totalling more than 80 separate stab wounds.
Fort, now 20, has pleaded guilty to manslaughter on the grounds of diminished responsibility, but a jury of 11 men and one woman will have to decide if he is guilty of murder.
Mr Hotten told the court: "At 3:23am on the morning of 28 July, 2008, a 999 call was made… The operator asked the caller for his address. He gave it and he added, 'I have killed my mother'.
"The operator said 'What made you do that?', and he replied, 'I can't honestly say why I done it. Please just get there and deal with it before I go mad'."
The case continues.