A man who stabbed his mother 11 times in a "drug-fuelled psychosis" has been jailed for 16 months.
Charles Mann, 21, appeared "manic and deranged" after bingeing on mephedrone, cannabis and alcohol, Hove Crown Court was told.
His mother Emma Mann locked herself in the bathroom of their Haywards Heath home and called police, despite suffering a punctured lung.
Mann admitted inflicting grievous bodily harm at a hearing last month.
He was told he could expect to be freed on licence on or around 7 April, having already served seven months on remand.
Prosecutor Amy Packham said Mrs Mann made a 999 call at 06:20 GMT on 29 December 2013.
Officers found the house in darkness and entered to see Mann, then 19, naked and covered in blood trying to climb out of a broken window.
Miss Packham said Mann told officers: "I am a paedophile, I do not want to live. Take me to the light. I can see the vampires."
As he attacked his mother, the court heard, Mann shouted: "This is the prophecy. I love you, but this is the prophecy."
The court heard Mrs Mann had injuries to her back, head, neck and arms, and needed surgery for multiple punctures to one lung and internal bleeding.
Mann also required treatment for serious injuries and spent much of his time under sedation in hospital before being transferred to a psychiatric unit and eventually to Lewes Prison, the court was told.
David Etherington QC, representing Mann, said he became involved in drug-taking after his GCSEs.
The court heard Mann had previously had hallucinations after taking drugs but never a violent reaction.
Mr Etherington said Mann had virtually no coherent memory of what happened but could only rationalise it as a suicide attempt by him in the grip of a delusion in which his mother somehow got involved.
The court heard he had since recovered from a "drug-induced psychosis" but remains "fragile and vulnerable".
Sentencing Mann, Judge David Rennie told him he would be helped and monitored upon release.
He said the case was "wholly exceptional" and that the opinion on both sides was Mann would have been "legally insane" at the time he "nearly ended" his mother's life.
Judge Rennie said that if he had been convicted of the original charge of attempted murder or intent to cause grievous bodily harm, he would have been sent to prison for "very many years".
Mrs Mann declined to comment as she left the court.