Kieren Smith, 17, stabbed 42-year-old Leah Whittle 94 times at her home in Benville Road, Weymouth, Dorset, on July 21. Sentencing Smith at Winchester Crown Court, Judge Guy Boney told him he would serve at least 15 years before he could be considered for parole.
He said: "You have been convicted of a deeply shocking and really utterly dreadful offence - that of killing your own mother in as brutal a way as can be imagined.
"You have cut short by many years the life of the very person who gave you life in the first place and expressing your crime in that way tells everyone the true horror of what you did."
– Judge Guy Boney
"I accept that you are not by nature an emotional man but you have shown not a smidgen of remorse."
The eight-day trial heard that Smith attacked his mother in the flat they shared before he lied to police, saying she had been killed by drug-dealers. The court heard that Smith had been expelled from school at the age of 14 and had spent the last two years alone in his room, watching DVDs.
Judge Boney said: "Your life revolved around watching DVDs alone in your room with an absence of emotional engagement. It is from that diet of constant DVDs that your fascination of knives came from."
He added: "That kind of unhappy and unfulfilling life that you lived must, in fairness, be put against your background, that your parents separated when you were little more than a baby and your family life was almost non-existent."
Nicholas Haggan QC, defending, said Smith's motive for the killing was unknown.
He said: "It's always difficult to give an explanation and in this particular case it's impossible. One will never know why the defendant did what he did. This is not an ordinary case; we accept it's very unusual for a young man to kill his mother."
Mr Haggan told how Smith, who has an IQ of 72 which puts him in the lowest 4% of the population, was excluded from school after becoming disruptive, leading to drink and drugs problems.
He said the defendant had become isolated and shunned contact with others to avoid getting emotionally hurt.
"He is a very lonely and unhappy individual who finds it very difficult or impossible to express his true emotions - he has told us again and again he finds it impossible to cry."
Mr Haggan added that Smith had shown little remorse and he believed his client may have blocked out the killing.
Richard Smith QC, prosecuting, told the jury that the defendant, who was 16 at the time, had an interest in knives and had a temper but said the reason for the murder would never be known.
The youth had denied the killing and said that men came down from Doncaster, South Yorkshire, to execute his mother because his brother had got into trouble over a drug debt.
He told friends and the police that he had seen a man or men attack his mother through a bathroom door and when they left he bolted the door, took some money from his mother's purse and escaped through a window and down a drainpipe.
Ms Whittle had moved back to Dorset after living in Yorkshire until her marriage broke down.
The court heard that her relationship with her son was often less than harmonious but the teenager told police the pair were close.
– Det Insp Marcus Hester, Dorset Police
"This case involved a particularly horrific and sustained attack on a woman who was unable to defend herself. This is a very tragic case where a young man, through his own violent actions, has killed his mother.
"He now has to face the consequences of these actions as well as to live with the loss of his mother. Our sympathy is with Leah Whittle's family and friends who are still coming to terms with their loss."