A new study by the University of Otago has found that nearly a third of Kiwis in their 40s have tried methamphetamine at least once in their lives.
The long-term study focused on the link between drug use and violence and tracked 1000 people born in Christchurch in 1977.
Participants were asked at the age of 21, 25, 30 and 35 about their use of amphetamine/methamphetamine, as well as their involvement in violence, either as a victim or perpetrator.
According to the study - called the Christchurch Health and Development Study - 28 percent of all participants reported using methamphetamine at least once between the ages of 18 and 35, and those who used it weekly or more were twice as likely to be the victim of intimate partner victimisation, compared to people who hadn't used the drug at all.
Weekly users were also five times more likely to be the perpetrators of violence.
The study showed 4.9 percent of participants reported using the drug at least weekly for a period of time between 18 and 35 years of age, while 11 percent had used the drug at least monthly at some point.
Twelve percent had used the drug but never more than one or two times a year.
Study director professor Joe Boden says it's the first time the connection between meth use and violence has been studied over a long period of time.
"It has long been suggested that amphetamines increase the risk of violence perpetration and victimisation, but evidence thus far has shown only evidence of association, rather than a direct causal link," says Dr Boden.
He also stressed that the study focused on the general population, as opposed to groups of people suffering either mental illnesses or addiction problems, which have been the subject of previous research.
According to data from the study, methamphetamine is the third most common drug in New Zealand, after cannabis and ecstasy.
Due to the link between meth and violence, Dr Boden said a reduction in the drug would lead to a lower rate of violent assaults in the country.
