Methamphetamine use and violence: Findings from a longitudinal birth cohort

Evidence linking illicit methamphetamine use to violence perpetration and victimisation comes primarily from cross-sectional studies. These associations have not previously been studied in a longitudinal general population sample.

Longitudinal birth cohort.

General population sample (n = 1265) born in Christchurch, New Zealand in 1977.

Participants were asked at age 21, 25, 30 and 35 about their frequency of methamphetamine use, and violence perpetration or victimization since the last interview. Violence was measured both in general, and within intimate partner relationships in particular. Logistic generalised estimating equations modelled the association between methamphetamine exposure and violence outcomes within each age period, adjusting for confounding factors and time-dynamic covariate factors. The dose-response profiles were explored via associations between heaviest methamphetamine use frequency from age 18-35 and violence outcomes in that period.

28 % of participants reported using methamphetamine at least once between age 18 and 35. Compared to no use, a history of any methamphetamine use in each age period was associated with an increased adjusted risk of violence perpetration (OR 1.60; 1.01-2.54), intimate partner violence perpetration (OR 1.55, 95 % CI 1.04-2.30), and violence victimization (OR 1.57, 1.00-2.47). Evidence for an association with intimate partner violence victimization was inconclusive (OR 1.09, 0.80-1.49). There was a dose response relationship whereby those who had used methamphetamine at least weekly at any time from age 18-35 had substantially elevated adjusted odds of violence involvement compared to people who used but less often, or had never used.

Methamphetamine use is an independent risk factor for violence perpetration and victimisation in the general population.