A coroner has been unable to determine the cause of death of a Rotorua mental health patient - a man his mother believes "slipped through the cracks".
Jared Peebles, 41, was found dead in his bed by staff at Pretoria Lodge (also known as Pounamu Recovery Solutions) in Rotorua on June 22 last year.
Mr Peebles, who had been diagnosed with schizophrenia, had checked himself into the lodge for respite care five days earlier after becoming unwell with hallucinations.
An inquest into his death was held in Rotorua last month and Coroner Gordon Matenga has released his reserved findings.
Coroner Matenga found Mr Peebles died as a result of "cardiac arrhythmia due to unascertained natural causes in a background of diabetes mellitus and obesity".
At the time of Mr Peebles' death his family had no concerns about his care and police confirmed there were no suspicious circumstances. Therefore his family's objection to a full post-mortem examination was upheld and a limited external examination done instead.
However at the inquest Mr Peebles' sister Tania Spence and his mother Kathleen Peebles both expressed concerns about the long-term care he had received.
Coroner Matenga said Mrs Spence was concerned about the lack of routine physical health checks including an ECG and blood test after her brother's change in medication.
"It was Mrs Spence's [a nurse] opinion that regular psychiatric assessment was not enough. Rather a psychiatrist should have asked for a medical opinion taking into account all comorbidities."
Mrs Peebles "felt that her son had slipped through the cracks", the coroner said.
Coroner Matenga said he had referred the case to Dr Christopher Kenedi at the Auckland District Health Board, a consultant physician, psychiatrist and Clozapine toxicity specialist.
Dr Kenedi concluded "with neither a prior RCG or an internal autopsy it is truly impossible to do more than guess" as to what caused the cardiac arrhythmia.
He recommended the Lakes District Health Board develop guidelines including all patients on the drug Clozapine having a baseline ECG and chest x-ray and routine reviews.
Coroner Matenga said he believed these would in large address Mrs Peebles' and Mrs Spence's concerns.
"However I find myself in the position of being unable to make any recommendations. This is because the cause of and circumstances of the death of Mr Peebles cannot be determined with a sufficient degree of clarity because a full post-mortem examination was not conducted.
"Without the full autopsy there is no evidence to determine why Mr Peebles died and whether the death could reasonably be attributed to QTc prolongation, from multiple antipsychotics or some other cause such as the lack of regular medical checkups or undiagnosed heart disease. To choose any one or more of these possibilities would be a guess."
He said he would bring the circumstances of the death to the attention of the Lakes District Health Board and provide it with a full copy of Dr Kenedi's report.
Mrs Peebles did not wish to comment on the coroner's findings. She had previously told the Rotorua Daily Post her son had grown up as a happy-go-lucky and sporty boy who started struggling with mental health issues when he was 19.