Another patient was held for 14 days at Canterbury DHB and a third for seven days at Bay of Plenty DHB. Dozens across the boards were held for more than 24 hours at a time.
Seclusion is considered potentially harmful, particularly to vulnerable people, because of its "toxic" combination of social isolation; a monotonous physical environment and institutional control. As such, it is monitored under strict human rights laws.
Waikato DHB had the highest number of seclusion hours of those specified, at 9475 by April for 103 patients. That increased to 10,560 by the end of May. That is double the DHB's target for the 11 months to May, which was 4078.
The DHB's Henry Bennett Centre had between 90 and 100 admissions each month, said the mental health and addictions executive director Derek Wright.
But there were only 102 beds, 49 of which were within regional forensic inpatient services.
One psychotic patient who had used cannabis and methamphetamine and violently assaulted staff and patients, was secluded for 23 days, he said.
A sharp rise in seclusion hours since mid-2015 was the result of a continually increasing level of occupancy and demand, and a growing number of patients with complex behavioural presentations, Wright said.
As echoed by other DHBs, Wright said they were working to dramatically reduce seclusion hours and had set up a steering group to target the issue.
Chief commissioner at the Human Rights Commission, David Rutherford, said the issue continued to come up.
"It's all indicative of a system that's not delivering to some of our most vulnerable."
Rutherford said detaining agencies could now expect greater scrutiny.
Auckland DHB said its goal was to reduce average seclusion hours by 50 per cent by May next year. Canterbury said its goal was to eliminate seclusion entirely.
Waitemata DHB, which operates the Mason Clinic, a regional forensic psychiatry service for Auckland and Northland, said a 50 per cent reduction target was set for this month.
Raising the issue
The issue of locking patients in their rooms at night was raised by the HRC in 2013 with the government's director of mental health but by June last year guidance for DHBs on the practice had still not been completed.
Under questioning in Parliament in May, Health Minister Dr Jonathan Coleman said the practice only happened in Capital and Coast and Waitemata DHBs' forensic services.
"Within those services, the decision to lock a service user in their bedroom at night is part of their individualised care plan, which is subject to robust and regular review," Coleman said.
International human rights expert Dr Sharon Shahlev in April slammed New Zealand for having high seclusion rates among prisoners, children, mentally unwell and the intellectually disabled.
Last year a Herald investigation prompted a call by Education Minister Hekia Parata for new legislation that would outlaw seclusion of children in schools.
It came after the Herald revealed the plight of Ashley Peacock, an intellectually disabled, autistic and mentally ill man who was kept in a tiny wing of the Tawhirimatea mental health unit at Porirua for five years, allowed outside for an average of 90 minutes a day.
The investigation prompted his freedom.
Injured and secluded
Meanwhile, the 2015/16 Monitoring Places of Detention report, which looks at mental health facilities, prisons and CYFS residences, recorded an injured patient in a secluded room.
During a visit to the Waitemata DHB-run He Puna Waiora in Auckland, inspectors found the patient who had been seriously assaulted 10 days earlier while an inpatient at Waiatarau Unit, also run by Waitemata DHB. It's understood he was injured and had not yet received surgery.
"The incident was not reported to the police, despite the service user's injuries requiring surgery," the report stated.
The report recommended all DHBs adopt a zero tolerance to violence by referring all assaults and serious incidents to police.
The report also found several adult inpatient units were unfit for purpose.
Of the nine adult acute facilities inspected, only one was open, and voluntary patients in some locked-door facilities were held with "no leave" status.
"We were concerned this could be considered coercive practice... It could potentially amount to arbitrary detention."
At He Puna Waiora internal courtyard doors were locked meaning patients were reliant on staff availability to go outside.
"So [they] did not always receive their minimum entitlement to daily fresh air."
Electro therapy
The Herald's OIAs showed that all of the country's DHBs, except for Wairarapa which sends mental health patients to Hutt and Wellington hospitals, also used electro convulsive therapy [ECT] in 2015.
Waikato DHB adult mental health and addiction services director Vicki Aitken said ECT was painless because patients had a general anaesthetic first and was used to treat severe depressive episodes.
She said patients and their families as well as the public were concerned about ECT but numerous reviews of published studies showed it was a "safe and important treatment option".