Voller, 19, made international headlines when disturbing images of him being mistreated in Darwin's Don Dale Youth Detention Centre came to light last year.

His mistreatment included being kept in isolation for up to one and a half months.

"You feel lonely. You feel like there's no-one there and no-one cares. You start talking to yourself and going mad," he told 60 Minutes.

He had spent eight years in detention since the age of 11, and from the age of 12 had been strapped into a chair multiple times, with his head encased in a spit hood.

"I guess I get that feeling for the first bit, of being trapped," he told reporter Liz Hayes.

"It makes you more agitated until you get too tired, and then when you get tired you start getting sick. That's about it. But it makes you increasingly more angry when you're in that. You just want to get out of it.

"It makes you more angrier, and to be honest it made me think more about suicide even more being in there, because I just wanted to be dead.

"I didn't want to be in that chair right then and there I would have rather died than sit in that chair for an extra minute."

Voller's lawyer, Peter O'Brien, labelled the detention centre "Guantanamo Bay".

"It was so shocking. It defied logic that a detention centre had allowed it to occur to a child, and that a government orchestrated and legislated to allow it to happen into the future was just mind-blowing," he said.

"The fact that it was known and it had been broadcast in the media, in the Northern Territory that that was happening. The response by the government was to legalise it, and that, to me, is abhorrent. It's mind-numbingly bizarre."

Mr O'Brien explained that his offending all stemmed from a "very significant childhood trauma ... and trauma as an infant".

"I had behavioural problems as a young kid. I guess trauma probably brought that on," Voller said.

"I guess in my thinking and my choices, how I made choices, like, and my wanting to fit in and be with the older kids and did silly things. Stuff like that."

Voller suffered ADHD and despite loving learning, he became increasingly hostile and disruptive at school because it was "when I'd get embarrassed when I couldn't do my work".

He was labelled the NT's most notorious young criminal, with 50 offences to his name.

"Most of those criminal offences occurred whilst he was in the detention centre itself," said Mr O'Brien. "And we know what was happening within the detention centre - it wasn't the type of system that was going to make a young boy a good man, and so the rap sheet developed."

But Voller kept standing up for himself, and lodging complaints to the Ombudsman. And eventually Four Corners aired the notorious video of his treatment in detention that led to a royal commission.

"Yeah, that's what saved him and that's the reason why I think he's probably still alive today, to be honest," said his older sister Kirra.

Voller has been out on bail doing an outback rehabilitation program that has helped calm him and learn from his mistakes.

"I apologise, for starters," Voller said when asked what he would say to his victims. "I know that what I did was wrong. There's nothing I can do to try to take it back. But I have made the effort to contact 'em and apologise personally myself."

Voller admitted that his actions spiralled out of control when he started using ice and became violent.

"I always felt bad, I'd go and cry after 'cause most of the time or thinking to myself, like, and like say, 'What?', 'Why did I do this?', 'What did I do?', and I'd be really upset with myself, because I know I'm better than that and I didn't need to do it."

When it came to whether he deserved the treatment he copped in detention, he told Hayes: "I thought that for a while. I thought that I did deserve it.

"It took me a while to realise that no young person deserves it, no matter what. No 11, 12, 13, 14, 15-year-old ... deserves to be assaulted. No young kid at all deserves to be put down, deserves to be told that suicide's a joke or that they're just trying to seek attention."

He now hopes to study law.

"Every young kid is worth something, and with just that little bit of help they can turn their life around from going from nothing, from going down the wrong path to going down the right path. And I'm an example of that."

Those experiencing personal problems are urged to contact Lifeline on 13 11 14 and lifeline.org.au.