A mental health patient who died of a suspected suicide was found to have been prescribed nearly three times the standard dose of the drug methadone by a doctor who was herself using opioid substitution medication.

The evidence comes as the coronial inquest into the death of Shaun Gray begins today.

Gray died while a patient at Palmerston North's Ward 21 in 2014. Months later 21-year old Erica Hume also died in the same ward. Her inquest is to be heard later this year.

Last May Chief Ombudsman Peter Boshier paid a surprise visit to the infamous ward and released a report describing it as one of the worst in the country.

He found that the 24-bed ward was over-capacity, Māori were put into seclusion at higher rates and there was urgent repair work needed.

Boshier also found there were a high number of medication errors, young people were often restrained and their access to telephones and leisure activities was limited.

A new $35 million ward was announced by the government several years ago and was due to open this year, however that opening date has been pushed back to at least 2023.

Coroner Matthew Bates this morning addressed Gray's family who were sitting in the public gallery.

"I must acknowledge the length of time in reaching this point. Some of it has been unavoidable, all of it nonetheless is regrettable," he said.

"Hopefully we can find some answers to exactly what has occurred.

"I hope it brings some further understanding and closure for Shaun's family and friends. And that we learn something to assist further deaths from occurring in similar circumstances."

The identity of the majority of the witnesses who will be called during the three-week inquest have interim name suppression.

The facts

According to the summary of facts on the morning of April 16, 2014, Gray went to the pharmacy to be given his daily medication of methadone.

After not being allowed to take this medication away with him he became agitated and called his care worker.

He then sent a text to his mother. She called the Alcohol and Drug treatment centre and explained her concerns.

A plan was then made to collect Gray and bring him to the centre. However, when staff picked him up he told them he'd taken a range of barbiturates and injected himself.

They took him straight to hospital where he was refusing treatment and was aggressive towards staff. He expressed suicidal tendencies and the call was made to keep him in hospital under restraints.

He was then transferred to the high needs unit in Ward 21.

While there the nurse who was originally charged with his care, did not complete his admission documentation before her shift handover.

There was also some confusion about the prescription of an abnormally high dose of medication to help Gray sleep. His doctor was called and a lower dose was given to him.

In actuality, Gray did not consume any of his sleep medication that night.

Later that evening, just before midnight he was found unresponsive in his room.

Methadone

Concerns had been raised about the levels of methadone that Gray had been prescribed by his Alcohol and Drug treatment doctor.

It was found that he was receiving nearly three times the amount of a standard dose.

One of the key factors being analysed is whether Gray's high dosage was prescribed appropriately and whether the reduction of that dosage was managed properly.

One of the considerations the coroner is dealing with is whether the reduction in his dosage contributed to his suicidal tendencies in April 2014.

The first witness who was called before the coroner was instructed to conduct a review into her prescribing practices in 2013 and found that on average she was prescribing far higher doses than her counterparts in other areas of the country.

"Shaun had been taking opiates for 15 years and had been on methadone treatment since 2004. So would have been highly tolerant to the sedating effects."

"But there needs to be adequate safeguards before this kind of prescribing is undertaken."

"I presume that all doctors prescribing in drug clinics are given the national methadone guidelines. They would be aware that there is a constraint in policy to a ceiling dose. So a doctor should be observant off that and compliant."

A second witness to give evidence commissioned the review into the methadone prescribing practices of Gray's doctor.

After the review which found she was prescribing the drug at high doses he met with the doctor and implemented a plan to have all her patients who were receiving a high dose slowly moved to a lower dose.

He also instigated a formal review into her prescribing practices, but the doctor returned to America before the investigation could be completed.

On questioning, the witness revealed that he was made aware that the doctor was also using opioid substitution medication, though he did not disclose what it was being used for.

List of issues

As part of the inquest there are pages of questions that Coroner Bates is seeking to establish answers for in relation to Gray's death.

Among those are whether the cocktail of drugs he was prescribed contributed to his suicidal tendencies and why the nurse charged with his care at Ward 21 did not convey his suicide risk in her clinical notes.

The staffing levels at the ward, which were found at the time to be sub-optimal, and the frequency to which Gray was checked on during his brief stint in the ward are also under scrutiny.

In terms of moving forward the Coroner Bates is hoping to establish what has changed at the Ward since Gray's death.

Specifically, have their prescribing practices changed to ensure patients receive the medicines they're supposed to and whether they've apportioned more staff to ensure high-risk patients are monitored more frequently.

SUICIDE AND DEPRESSION
Where to get help:
• Lifeline: 0800 543 354 (available 24/7)
• Suicide Crisis Helpline: 0508 828 865 (0508 TAUTOKO) (available 24/7)
• Youthline: 0800 376 633 or text 234 (available 24/7)
• Kidsline: 0800 543 754 (available 24/7)
• Whatsup: 0800 942 8787 (12pm to 11pm)
• Depression helpline: 0800 111 757 or text 4202 (available 24/7)
• Anxiety helpline: 0800 269 4389 (0800 ANXIETY) (available 24/7)
• Rainbow Youth: (09) 376 4155
If it is an emergency and you feel like you or someone else is at risk, call 111.