Robert Moore stopped smoking synthetic cannabis a year ago, but is still recovering from its effects and does not know when he will be "right" again.
The 24-year-old told the Herald last year that after four months of smoking Kronic, his life began to "fall apart".
He developed a daily habit, spending about $80 a day on Kronic, and hit "rock bottom".
Now living in Australia, Mr Moore said yesterday he was only just starting to feel almost back to normal.
"But I think it still has an effect. I can't drink any more because I get quite violent. That stuff definitely twists you up for a while," he said.
He said the lows he experienced after using Kronic were scary.
"It's a really dark place. You can only know what the psychological damage is when you've been there.
"I definitely feel better now, but it takes a while to get back from that dark place. It really sets you back a lot when you're using."
He thought it would take more than warnings from experts to stop most Kronic users. But he wanted to get the message across about long-term effects.
"Think about what you're doing to your brain ... It's pretty vulnerable and doesn't need the chemicals."
In the work we do in the community and away from work we've encountered several families with young teens who have become hooked on Kronic and its many variants. It's nasty stuff, with significant anti-social side effects. And it is especially worrying to see young teenagers becoming hooked on the drug at an age when their brains and their bodies are still developing. It's turning young people, especially young men into petty criminals who steal to pay for their addiction. And it's causing trauma to the families of these young people who are seeing good kids turned into someone they don't recognise.
So we applaud Peter Dunne for his moves against those who peddle this insidious menace. Our young people don't need to be dabbling in this toxic chemical mix, blissfully oblivious to the long-term damage gauntlet that they are running.