Callum Cameron sentenced for stabbing murder of his mother Carol Cameron in their St James home

A man who stabbed his mother to death at their Perth home while under the influence of psychedelic drugs has been jailed for life with a 20-year minimum term.

Warning: This story contains details that readers may find distressing.

The court heard Carol Cameron called paramedics to her St James home on August 10, 2020, worried her son Callum had overdosed on a cocktail of drugs, including the psychedelic DMT.

The then 27-year-old fatally stabbed his mother 62 times in their kitchen after paramedics tried to take him to hospital.

Cameron faced a judge-alone trial in the WA Supreme Court in March after pleading not guilty to his mother's murder, telling the court he was instead guilty of the lesser offence of manslaughter.

But his defence was rejected, and Cameron was convicted guilty of murder in August.

Mother tried to escape attack

The trial heard when Ms Cameron, 63, made the triple-0 call about her son's overdose, she described him as not violent.

But by the time paramedics arrived and tried to take Cameron to hospital, he had become agitated.

Ms Cameron followed her son into their kitchen, trying to encourage and "coax" him to comply with ambulance officers.

Ambulance officer John Bowring told the court he lost sight of the pair, then heard the sound of cutlery moving and Ms Cameron shouting: "He's hurting me. He's stabbing me".

Mr Bowring told the court he could hear stabbing noises before Ms Cameron came back into his line of sight, crawling and clawing on the floor as the attack continued.

Police were called and found Cameron sitting on a couch with blood on his hands, looking "remarkably calm", while his mother lay dead in another room, with 62 stab wounds to her face and body.

Officers were forced to restrain Cameron with a taser.

Defence lawyer Helen Price said the incident unfolded quickly.

"Everything blew up almost in a matter of minutes," Ms Hill told the court.

"Nothing will get his mother back. He will have to live with this for the rest of his life."

Son intended to kill mother: judge

In sentencing, Justice Joseph McGrath said he accepted the incident wasn't premeditated, but there was a clear "intention to kill".

"Your attack was extremely violent. When your own mother attempted to retreat, you pursued her and continued your ferocious attack on her," he said.

"Your mother should've been safe in her own home from her own son."

The court heard Cameron had an extensive history of using illicit drugs including methamphetamine and heroin, starting from the age of 14.

Kind-hearted woman

Ms Prince told the court her client, who had a long history of undiagnosed mental illness, was "in a state of delirium and acute confusion" at the time of the attack.

He had recently broken up with his girlfriend, leaving him in a state of anxiety and depression.

Ms Price told the court Cameron "accepted he was responsible for the death of a mother he loved", whom he described as a kind-hearted, sensitive woman.

Cameron broke down during the sentencing.

"I didn't know I was going to stab her though," he called out as the judge spoke.

Cameron's prison sentence, and subsequent 20-year non-parole period, has been backdated to August 2020 to reflect the time he's already served.