Imprisonment among people who use methamphetamine: Preliminary results from a prospective cohort study.

Author: Michael Curtis, Brendan Quinn, Jack Stone, Lisa Maher, Paul Agius, Mark Stoové, Bernadette Ward, Rebecca Jenkinson, Matthew Hickman, Peter Higgs, Paul Dietze

Theme: Epidemiology & Public Health Research Year: 2023

Imprisonment is associated with numerous and often enduring adverse outcomes. Methamphetamine is the most commonly used illicit drug among people entering Australian prisons. However, the incidence and factors contributing to imprisonment of Australians who use methamphetamine are poorly understood. In a prospective study of people who use methamphetamine, we determined incidence of, and explored factors associated with, self-reported imprisonment.

Data (2017–2022) were from VMAX, an ongoing cohort study of people who smoked methamphetamine at least monthly at study enrollment in Victoria, Australia. Crude imprisonment rates were calculated; associations between imprisonment, demographics, and lagged (one interview) homelessness, substance use, and service use characteristics were estimated using multiple-event discrete-time survival analysis.

Among 541 participants (interviews: median=3, range=1–8), 108 (20%) reported a total of 151 imprisonments (range=0–4) during 1761 person-years (PY) of observation, a crude imprisonment rate of 85 (95% confidence interval [95%CI]: 72-99) per 1000 PY. Using methamphetamine weekly or more (adjusted hazard ratio [AHR]: 1.68, 95%CI: 1.16–2.44) and a previous history of adult imprisonment (AHR: 4.21, 95%CI: 2.85–6.23) were associated with an increased hazard of subsequent imprisonment. Older age at baseline (AHR: 0.94, 95%CI: 0.92–0.97), female or ‘other’ gender (versus male; AHR: 0.58, 95%CI: 0.37–0.91) and employment (AHR: 0.61, 95%CI: 0.38–0.98) were associated with a reduced hazard of subsequent imprisonment. Homelessness, recent injecting drug use and being Aboriginal or Torres Strait Islander were not associated with imprisonment.

In a cohort of people who use methamphetamine in Victoria, Australia, we observed an imprisonment rate 40-fold greater than the general Australian population. There is a clear need to address imprisonment rates among this group. The use of non-custodial responses to drug-related offences, and initiatives which improve employment outcomes, or reduce frequency of methamphetamine use, could reduce imprisonment among people using methamphetamine.

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