A man who was in a drug-induced psychosis when he used three methods to murder a NSW schoolboy has been jailed for at least 17 years.
Chadley Sheridan attacked the 16-year-old in the youth's bedroom, smothering him with a pillow, strangling him with his bare hands and with an electric cord attached to a pedestal fan.
The 25-year-old was found guilty of murder in September, after the jury rejected his defence of mental health impairment.
While Sheridan did not deny killing the teenager, he pleaded not guilty to murdering him on March 15, 2021, in Charlestown in the NSW Hunter region.
The issue for the jury was whether Sheridan was mentally impaired at the time or whether his psychosis was drug-induced.
In the NSW Supreme Court on Friday, Justice Peter Garling jailed him for 25 years with a non-parole period of 17 years.
He was satisfied that at the time Sheridan killed the teenager he was criminally responsible for the death and not substantially impaired by any abnormality of the mind.
He was suffering from a drug-induced psychosis as a result of self-induced intoxication after using ice and other drugs.
"I am satisfied that the offender was well aware of a causal connection between his taking of drugs, particularly ice, and suffering psychotic episodes," Justice Garling said.
His sister testified that for weeks after her brother moved to live with her in Newcastle in January, he was doing well, but from late February he started using ice and she kicked him out of home.
In the lead up to the killing, he took ice intravenously as well as other drugs and witnesses described him as being "completely off" and really upset.
When his sister spoke to him on the phone he seemed to be scared and like a little child who was stuttering and couldn't express himself properly.
The teenager was found dead on the floor by a relative who had welcomed Sheridan into the Charlestown home.
Victim impact statements from his family made clear that his death had caused significant harm and distress, the judge said.
He accepted Sheridan had been experiencing command hallucinations in the form of voices directing him to act in a certain way or else he would suffer certain consequences.
"I am satisfied that he was impaired in the sense that he did not know that strangling the deceased or killing him was morally wrong," Justice Garling said.
But the impairment was caused solely by the temporary effect of voluntarily injected ice on the night of March 15 and on previous days.
"It was a violent assault by the offender, upon an adolescent in his own bedroom, which involved the use of three methods of attempting to kill the deceased with the intention of so doing."
Sheridan, whose criminal history included drug and driving-related offence, had struggled with mental health issues and drug addiction for many years.
"Although those matters are intertwined, I am satisfied that the offender suffers from chronic mental illness including ADHD, PTSD, a major depressive disorder and a substance disorder," the judge said.
"He is at an increased risk of experiencing drug-induced psychosis."
Medical records showed Sheridan suffered previous episodes and had been on notice that using ice could cause him to become psychotic.
He had expressed regret and remorse for the killing.
