Anthony Murphy, from 23 Dunmanus Park, Knocknaheeny, Cork, died on June 16 last year after suffering a heart attack at home.
He was on four different types of medication to treat his schizophrenia.
Cork Coroner’s Court heard that Mr Murphy had a history of depression and of cocaine and cannabis abuse.
But Dr William Kealy, a pathologist at Cork University Hospital (CUH), told the inquest that an autopsy showed Mr Murphy’s heart and coronary arteries were normal.
Toxicology tests showed no traces of alcohol, cocaine or cannabis in the blood.
Traces of opiates were within the therapeutic range for the prescribed medication, he said.
Dr Kealy told coroner Myra Cullinane that Mr Murphy’s death was sudden and unexpected and associated with a heart attack in a young man with a history of drug intake.
But he said it was difficult to exclude the mixture of significant schizophrenia medication having an effect on his heart.
Mr Murphy had been taking his medication erratically and had been admitted to hospital two weeks prior to his death following an overdose.
But his family said his behaviour was normal afterwards.
However, he began to feel unwell while at home on June 16.
His sister Stephanie said he was disorientated, drowsy, and began to snore on the couch at around 4pm.
That was not unusual because of his medication, she said.
Tim Farrell, who had been Mr Murphy’s probation officer since 2002, told the inquest that the anti-depressants made his client very drowsy.
Mr Farrell said he called to the Murphy home early on June 16 to tell Anthony he had secured a place for him on a Safety Pass Course with a view to getting a job on a building site.
“He sounded optimistic about life,” Mr Farrell said.
However, Mr Murphy’s father, Denis, said the family became concerned for him that evening.
His condition worsened at about 8pm. A doctor arrived at the hose and began CPR and called for an ambulance.
Mr Murphy was taken to the Mercy University Hospital but was pronounced dead a short time later.
Coroner Myra Cullinane said the appropriate verdict in this case was death due to misadventure and she extended her sympathies to the Murphy family.