The man who cut off his finger, cooked it with vegetables and ate part of it says the health system does not do enough to help the mentally ill.

The South Island man, who asked not to be named, spoke out after reading a story about his case in the Herald last month based on a psychiatric journal report by his clinicians.

Clinical psychologist Craig Prince and forensic psychiatrist Erik Monasterio wrote of the case of "self-cannibalism", the first of its kind known in New Zealand and one of only eight reported in the world, to alert colleagues to the rare behaviour.

The "Mr X" of the journal article contacted the Herald because he wants to encourage people to seek professional help if they are mentally unwell.

"Hopefully someone with a mild case of depression or something reads it and then thinks, 'Jeez, I don't want to get that bad', and then gets help, they stabilise after a wee while and they lead a reasonable life - which unfortunately I haven't been able to do.

"I've been hospitalised so many times. I remember the first time I went to hospital, I met this guy, he might have been about 55, he labelled himself as a professional lunatic.

"Now that I've been on the [sickness] benefit for however many years and I'm not capable of working, holding down a job, that's exactly what I am."

Mr X, now 30, cut off the little finger of his left hand after tying it off with a shoelace for a tourniquet in 2009, cooked it in a pan with vegetables and ate its flesh.

The report says he had low moods, sometimes thought of suicide and had a "vulnerable personality structure".

He had been physically assaulted by two men and later fantasised about killing and eating them.

He was moderately depressed at the time of the finger incident and not fully compliant with his medication, but was not psychotic and had not consumed drugs or alcohol, the journal report said.

Mr X said he did experience psychosis, but it ended by the time he was assessed in hospital.

He said some mental health workers had suggested he might have obsessive compulsive disorder or a personality disorder, but he struggled to convince them he was experiencing more than depression.

"I speak to them, the truth, I string a few words together in a sentence and I don't seem to be out of it or anything. That's because when I see them, it's usually afterwards."

He said he disliked being in a psychiatric hospital, but believed he should be admitted to one long-term.

"I have lost all faith in the system. You have to say you are going to kill someone or kill yourself [to receive attention]."

He regretted cutting off his finger, "which was ultimately a very stupid idea".

"I converted to vegetarianism about eight years ago. I went on and converted to Buddhism. The only flesh I have eaten [since] is my finger."

Mr X was now flatting with some close friends. He told them what he had done. They didn't freak out, "not in front of me, obviously. I think they were more concerned about me than themselves or anyone else".

"They asked me, 'What did it taste like? Does it taste like chicken or pork?"'

Mr X didn't know. "I haven't eaten chicken or pork in such a long time."

* If you need help, see your GP, your local hospital or call LifeLine on 0800-534-354