Five-year Changes in Methamphetamine Use, Dependence, and Remission in a Community-recruited Cohort

Objectives: Investigate patterns of methamphetamine use over time, specifically factors associated with remission from dependent and harmful patterns of use; and examine drug treatment and health/support service utilization pathways among people who use methamphetamine. Methods: People who regularly use methamphetamine were recruited from nontreatment settings in Melbourne, Australia, in 2010, and followed up twice over 5 years. Trajectories of past-month methamphetamine use and methamphetamine dependence were mapped. Random-effects logistic regression modeling identified factors associated with these outcomes. Results: Overall, past-month methamphetamine use and methamphetamine dependence decreased among the cohort over the study period. Variability in methamphetamine use and dependence trajectories was observed; 56% of participants achieved past-month abstinence; however, 14% subsequently relapsed and 44% reported past-month use at every time-point. During the study period, 27% of participants were never classified methamphetamine-dependent, 30% remitted from dependence, and 23% were consistently classified dependent. Factors independently associated with past-month methamphetamine use included male sex and poor physical health. Factors independently associated with methamphetamine dependence included poor physical health, low self-perceived social support, current mental health medication prescription, and current engagement with drug treatment services for methamphetamine use. Engagement with treatment and health/support services remained low (12%-22%) over the study period. Conclusions: Our findings indicate people who remit from methamphetamine dependence, reduce their frequency of use or cease entirely can maintain this over long periods. Initiatives addressing social determinants of health could be optimal for combating methamphetamine dependence. Community-based frontline service providers should be educated in relation to appropriately addressing methamphetamine use.