A "reclusive" teenager stabbed his mother to death at their family home, then called emergency services saying: "I have killed my mum", a court heard.
Jamie Fort stabbed Patricia Fort, 57, more than 80 times in the living room of their home in July 2008 as his father and younger 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 July 28, 2008, as she slept in the lounge.
He then called emergency services from the house in Lanchester Way, 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 July 28, 2008, a 999 call was made from 226 Lanchester Way in Castle Bromwich.
"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."'
When asked how he killed her, he told the operator: "I took the knife from the kitchen, stabbed her multiple times, everywhere", the court heard.
Mr Hotten said: "He said his mother was on the living room floor, that she had been sleeping. He had woken her up and said 'Hi'."
The court heard that, when two police officers arrived at the house, Fort answered the door wearing just a pair of tracksuit or pyjama bottoms, with blood on his hands.
He told the officers: "The knife's in there", pointing to the kitchen, as they found his mother lying on the living room floor.
Fort's father, Paul Fort, and younger sister, Petra, who was just 16 at the time, were woken by police as Fort was arrested on suspicion of murder, Mr Hotten said.
He said Mrs Fort, who worked as a catering manager at a school, was taken to hospital but was pronounced dead just after 4am.
"There were 35 wounds and groups of wounds to the body of the dead woman," he said. "Eighteen to the face and neck and 17 to the chest, back and abdomen.
"She had been the victim of a sustained assault with a knife.
"There were no cuts to the upper limbs to suggest that the deceased had tried to fend off the knife."
Mr Hotten said there was no issue as to who was responsible for the death of Mrs Fort, but the issue was why her son had killed her.
The court heard that Fort was "reclusive", rarely leaving the house.
"A picture emerges of a young man on the one hand bright and intelligent but on the other hand reclusive and socially isolated," Mr Hotten said.
"Whereas Jamie Fort appears to have had a particularly difficult relationship with his father, his relationship with his mother was much better."
He said that, since July 2008, experts had found the teenager was suffering from a mental disorder called "dissociative disorder" when he carried out the attack.
"Such disorders are said to disrupt awareness and perception and mean the sufferer is not in control of his actions," he said.
He said the jury would have to decide whether they thought Fort was suffering from a mental disorder at the time, and if it did substantially reduce his mental responsibility.
"This is not a case about whether this killing took place or who was responsible for it, the question is why," he said.
Fort's father Paul told the court his son, who was awaiting his A-level results at the time of the killing, rarely went out and was the "complete opposite" of his younger sister.
"He didn't mix with people that much, he hardly ever went out," he said.
"He was a nice young lad, intelligent, did not mix outside because of anti-social behaviour on the estate. He was just quiet and kept to himself."
Fort spent most of his time on the computer, listening to rock music or reading books, his father said.
The court heard his parents tried to encourage him to meet people, once arranging a family holiday to Kent so he could meet up with a girl he had met on the internet.
Mr Fort said the whole family had previously attended church together on a Sunday, but at the age of about 15 Jamie decided he did not want to go any more, though they did not know why.
He said on the night of his wife's death, she had been watching Midsomer Murders and stayed downstairs when he went to bed.
The first thing Mr Fort knew of the attack was when he was woken by police in the house.
He said when he saw his son in handcuffs at the bottom of the stairs he looked "quite calm", and said to him: "You will hate me for this."
Mr Fort, a Royal Mail worker, said he once suggested to his wife that their son should see a psychiatrist because of his general behaviour and their strained relationship, but nothing came of it.
He told the court his son "loved his mother" and said the attack was "completely unexpected".
Fort's sister Petra, now 18, said the family had not been particularly close and both she and Jamie regularly ate their meals in their bedrooms.
She too was woken up by police in the house after Fort had stabbed their mother.
Fighting tears as she gave her evidence, she described herself and her brother as "different".
"He had two friends that used to come and see him at our house but he didn't really go out with them," she said.
"They only came around every so often. He went out with those friends once that I can remember."
She said she had not noticed a change in him, other than he had not been sleeping well.
Miss Fort told the court that Jamie and their father did not get on.
"Jamie didn't like him," she said. "He used to tell him that.
"He used to say that he doesn't like him."
She said she did not know of any problems Fort had been going through at school, but said he dressed "differently" and had started dressing in a "rock style" after becoming interested in rock music.
The jury was played a recording of the 999 call Fort made at 3.23am on the morning of his mother's death.
During the call, which lasts just under four minutes, he can be heard to say "I've killed my mother", and "I've killed my mum", and describe how his sister and father are upstairs in bed.
Today, Fort broke down in tears as evidence of his mother's injuries were read to the court.
Mr Hotten read from a pathologist's report, which found 35 separate stab wounds and groups - some with as many as 13 stab wounds close together.
The court heard that Mrs Fort was stabbed more than 80 times, including her face, neck, chest, abdomen and the back of her head.
Mr Hotten said she died of blood loss from the effects of the multiple wounds, and at least moderate, sometimes severe, force had been used.
The court heard there was blood staining on the floor of the living room but not on either sofa, though it was possible Mrs Fort had been attacked on the sofa and not started bleeding until she had moved.
The kitchen knife with a 12cm blade had a slightly damaged handle and a rivet missing, but it was not known when this had happened, the court heard.
Mr Hotten said Fort had given a no comment interview to police and had no previous convictions.
The case at Birmingham Crown Court was adjourned to tomorrow morning, when the defence will call several psychiatrists to give evidence on Fort's mental state at the time.
The 20-year-old, of Lanchester Way, Castle Bromwich, denies murder but pleads guilty to manslaughter by diminished responsibility.