CHADLEY Sheridan knew what could happen to him if he used methamphetamine.
In the past, when he had suffered troubling episodes of psychosis and become delusional, each time it had been "closely linked" to his use of ice.
But despite knowing all this, Sheridan relapsed into drug use in March last year, injecting and smoking ice, drinking alcohol and using other drugs.
He essentially took a risk with his mental health, consuming anything he could get his hands on, including taking and injecting "unknown substances".
Within a few days, an innocent boy, a 16-year-old, would be dead, strangled in his bed in a unit in Charlestown in the middle of the night.
Fast forward and on Thursday, after facing a trial that focused on his mental state at the time of the unprovoked attack, Sheridan was found guilty of murder, a jury finding the psychosis he was suffering at the time of the killing was caused solely by using drugs, particularly methamphetamine.
Sheridan, 25, did not deny killing the teenager, but pleaded not guilty to murder and had raised a defence of mental health impairment, claiming he did not know what he was doing was wrong because he was suffering from psychosis.
There was no dispute that Sheridan was psychotic at the time of the killing; both experts agreed he was experiencing auditory hallucinations and bizarre delusions.
But the central issue during the trial was what caused Sheridan to become psychotic. Was it temporary and solely triggered by his drug use, particularly injecting and smoking methamphetamine in the days before the attack. Or, as the defence claimed, was Sheridan's psychosis caused by an underlying chronic disorder that was not temporary and not caused by drugs but exacerbated by using them.
It was a narrow issue but the difference would determine whether Sheridan had available to him a defence of mental health impairment and was, therefore, guilty or not of murder.
Sheridan, from Evans Head on the far north coast, had moved to Newcastle about two months before the teenager's death.
He had been living with a family member at Mayfield, but had been kicked out of home and was staying a few nights with the teenager and his father in a unit in Charlestown Road.
Sheridan had been drinking alcohol and using drugs on the evening of March 15, 2021, when the teenager's father and his father's friend left the unit about 10pm, leaving Sheridan in the loungeroom playing video games and the teenager asleep in his bed. When the teenager's father returned about an hour later, Sheridan was crying and upset and then later was "unable to settle down", Crown prosecutor Rob Munro told the jury during his opening address. It was not until after midnight, when the teenager's father checked on him in his bedroom and found his body on the floor, that the alarm was raised and paramedics were called.
It was not clear exactly what happened in the bedroom, but Sheridan appeared to try three methods to strangle the teenager.
"It was an attack on a boy who was minding his own business and trying to go to sleep," Mr Munro said.
Sheridan fled the unit a few minutes later and was arrested at a service station at Thornton about 1.50am.
During an interview the next day with police, Sheridan said he had consumed a drug that made him feel "very different" and "not himself". He said he had "f---ed up thought patterns", relating to his work at a funeral home and said those thoughts included "that to turn into a man he has to kill himself".
"He said he was taking messages from the universe, subconsciously and consciously," Mr Munro said of Sheridan. "He thought he had to do it to become someone else. "That he never formed the opinion that he'd kill [the teenager], that was simply created."
Sheridan admitted to police that he had strangled the teenager and immediately after had made the call to the teenager's father where he had become upset.
During his closing address, Mr Munro said Sheridan appeared to be functioning well before relapsing into drugs in the days before he suffered the psychotic episode and strangled the teenager to death.
He discussed the competing evidence of the experts - consultant forensic psychiatrist Dr Kerri Eagle and forensic psychiatrist Dr Olav Nielssen - and said there was no evidence Mr Sheridan had suffered any symptoms of psychosis in the last 18 months while he was in jail, meaning, he said, the psychosis he suffered on the night of the killing was temporary, caused solely by drugs and not a chronic or ongoing mental illness.
"If this was a chronic illness made worse by the use of ice, you might think there would be a single example of the accused having psychosis in the absence of ice," he said. "That is not here."
And, perhaps more damning for Sheridan, Mr Munro said his previous episodes of psyhcosis had all been "closely linked" to using ice, meaning Sheridan knew what could happen when he used the drug.
Despite this, in the days before the teenager's death, Sheridan relapsed into drug use after six months of being clean, injecting and smoking ice as well as using other drugs and alcohol.
The result was within a few days he had slipped into psychosis and an innocent boy lost his life.
After listening to the expert evidence and closing addresses and after deliberating for about eight hours the jury returned to Newcastle Supreme Court first thing on Thursday and found Sheridan guilty of murder, finding the psychosis he was suffering at the time of the killing was caused solely by drug use.
Sheridan will face a sentence hearing in November.
