Methamphetamine has become so endemic in New Zealand there are now reports of primary-age children taking the drug to school.
Addicts and former users told RNZ they had begun using methamphetamine - known as meth or P - from as young as age 6.
And schools and social workers said they were struggling to cope with the even greater number of children affected by their parents' P use - from birth defects to neglect at home.
This story is part of Broken Bad, RNZ's in-depth look at New Zealand's methamphetamine problem. Read more here.
Former addict Kahn Steiner, now in his 20s, was introduced to the drug by his own parents.
"I was a 6-year-old kid selling meth with my dad, while my mum worked as a prostitute in the clubs," he said.
"By the age of 15, 16 I had become fully addicted to methamphetamine [and] I had learnt how to cook methamphetamine by the time I was 16."
Social worker Fiona Watson said the problem with children exposed to or accessing the drug was getting worse.
"We've heard stories about kids taking stuff to school to maybe take to their aunties or uncles - this is like 10 or 11-year-olds," she said.
Tai Tokerau Principals' Association president Pat Newman said every class in Northland would have children affected by their parents' drug use.
That could range from children inhaling the fumes from meth being cooked or smoked at their home, or mothers being pregnant and using meth, to children going hungry and not being properly looked after.
"If you're talking impact from lack of food [or] parenting, through to the very worst parts of P's impact on our kids, one or two in a classroom would be minimum."
Students suspected to have been affected by meth use tended to have developmental problems, Mr Newman said.
"Their socialisation skills are sort of at the one to two-year-old age; we're getting an effect through increased violence and irrationality."
New Zealand Principals' Federation president Whetu Cormick said while he had not heard stories of children with methamphetamine at school, he agreed there was a growing problem with children being born into families with P-addicted parents.
"Increasingly we're hearing from colleagues across the country, about the concern they have with children presenting at school who are - as awful as it sounds - P babies," he said.
"The challenge that we have is finding appropriate support from psychologists and special education services to help schools and teachers deal with the challenges these children are presenting."
While there was plenty of research on foetal alcohol syndrome, there was very little information about the effects of methamphetamine.
"Teachers are often feeling around in dark for strategies that work with these young people," Mr Cormick said.
"The sooner we get some research around this, the better support will be put in place."
Grassroots group P-Pull co-founder Dennis Mokalio said he wanted to see education about methamphetamine introduced at primary school level.
The group had been speaking to Te Puni Kokiri in a bid to spread their anti-P message to schools.
"Hopefully our presentation will convince them to at least let us start with our Māori schools, because if the government don't want us to help society, then we need to focus on our people first," Mr Mokalio said.