Two years later he was smoking weed daily. Around the same time, Kane was diagnosed with ADHD and prescribed Ritalin to help him stay focused at school.
But he soon discovered that overdosing on the medication had a different effect.
"It's like coke, just short lived, just a stimulant. It makes you feel content, and made me interested in the subject in class, whereas normally I'd switch off.
"I was on one three times a day. Then I went and saw my psychiatrist and said it wasn't working, I needed more. He was like 'okay we'll give you one and a half pills, three times a day'. Then two pills, then three pills, three times a day.
"That's when he said 'that's as much as I can give you', and that was 240 pills a month. I was taking them within a week."
Kane believes his abuse of Ritalin led him to experiment with P later in life.
"For ages, I would earn $800 a week and I would spend the whole lot on that (methamphetamine) and payday was Thursday and it was all gone Saturday, like the whole lot. It was a vicious cycle.
"I got into it really heavy when I was 22. I lived for it for about 12 years. It was just my life.
Becoming a parent didn't change anything.
"I had kids at 25. My first kid was born and straight after she popped out I went and got some crack, went and got some meth. It was all about meth. I didn't really know I had a kid, sort of didn't even really care."
Kane's addiction meant he missed out on seeing his kids grow up. But he was careful to never smoke methamphetamine in front of them.
"I never done it around the kids. I never even really did it at home, much. I would pretend I was going to the toilet and go in there and have a quick puff and sit in there for ten minutes, I would have the window open and just blow it out the window.
"I couldn't even take a day out of the meth to spend with my kid on their birthday. I feel sorry for them because their Dad was more focused on his addiction than them.
"I see Dad's out now with their kids at the lake, focussing on them, with their kids on their shoulders, you know, all about the kids. That wasn't me.
"Meth distanced me from them, I was present but I wasn't. Like I was there but I was in another world like I just used to sit out in the shed while they were all inside running around...
Unintentional child neglect is something Paeroa Children's Carehouse manager, Melanie Budge has seen plenty of in her work helping children and families affected by methamphetamine.
"What happens is that the people that are using are in a euphoria. They don't see the neglect that they're giving their children. They think that because they're happy, their children are happy. They are doing things that they wouldn't dream of if they weren't involved in taking methamphetamine," Budge said.
In the small community of Paeroa where she's based, she says there are at least 30 families affected by the drug.
"When there's a drug-involved they put that before food. Methamphetamine is expensive. So you go down the poverty track. We do a lot of food here. Food is something we can access, we can give to children freely, that's one thing we can provide children, a safe place.
Johnny Kane has seen parents smoke meth while children are present.
"I've seen it, people smoking in front of their kids. Kids pick up the pipe, the parents say 'put that down'. I've seen it, I've been around it, I couldn't say anything because I was using as well, I didn't care, I didn't give a f***."
Kane is still working on his addiction recovery and trying to re-establish a relationship with his children.
"They're very forgiving, they still love me hard out, but I'm still finding my feet.
Kane knows he will escape the addiction.
"I'm not a bad person, I was sick. I'm not even a bad person trying to get good. I'm a sick person trying to get well.
Addiction is a disease. All it wants to do is take your life, it wants to eat your soul and destroy you. People can judge me all they want for being an addict, it's not like I chose to be one."
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