A woman found not guilty of a stabbing spree in Wellington because of insanity was suffering from a "major mental illness" on the day, including paranoid delusions and hallucinations.

She also assaulted her doctor, believing he was evil and trying to poison her.

In the High Court at Wellington today, Justice David Collins found the woman, whose name is suppressed, not guilty because of insanity to a charge of murder, one of assault with a weapon and three of wounding with intent to cause grievous bodily harm.

A 67-year-old man died and four others were wounded in an attack at a Johnsonville house in June last year.


Defence lawyer Mike Antunovic accepted the woman "was involved and committed the act in relation to each of the five charges".

On the day of the alleged offending, the woman saw her doctor for help. She was then referred to hospital where she was seen by a crisis team. They tried to get her to take medication, which she hadn't been doing for months.

Forensic psychiatrist Dr Justin Barry-Walsh told the court, in a hearing to determine the woman's mental health, she assaulted her GP, believing he was evil and trying to poison her.

She was also deeply suspicious of the crisis team.

Dr Barry-Walsh interviewed the woman within 48 hours of the alleged offending, when she was "unable to reason with a moderate degree of sense and composure as to the moral wrongness" of her actions.

"I found her to be very unwell indeed, very distressed, disorganised."

The woman would contradict herself. Before the alleged offending, she'd suffered hallucinations and was fearful for her life.

Another forensic psychiatrist, Dr Philip Brinded, said the woman's mental health problems began in 2008 and she had spent time committed under mental health legislation.

"At the time of the alleged offending she was recognised as suffering from major mental illness, probably schizoaffective disorder."

Dr Brinded said the woman hated the side-effects of her treatment.

"Unfortunately, whenever she stopped her medication her history shows that over a period of months she becomes extremely unwell."

By June, the woman was suffering from "paranoid delusional beliefs", including that people wanted to poison her. She was hearing voices telling her what to do and criticising her.

On the day, she was in a "psychotic state". "She was fearful of her life ... Some of the hallucinations were clearly quite terrifying for her," Dr Brinded said.

"She told me at the time the alleged offence happened, she was feeling incredibly overwhelmed."

She was not able to think rationally about her alleged wrongdoing and thought it was the right thing to do.

Justice Collins agreed with the expert evidence and the woman's not guilty pleas. He also decided she should remain as a special patient in hospital "until such time as it's determined that that restriction is no longer required."

A hearing on name suppression will take place next week.