Why was this study done?
• Individuals with criminal histories experience high rates of opioid dependence and premature mortality.
• Deaths caused by opioids are rising acutely and offenders are at risk.
• Adherence to opioid substitution treatments (OSTs), such as methadone, has been shown to reduce the risk of death during custody and immediately following release.
• Little is known about the long-term association between methadone adherence and mortality.

What did researchers do and find?
• This study integrated population-level data including prescriptions, convictions, and deaths in British Columbia (BC), Canada spanning 1998–2015.
• We examined the risk of all-cause and cause-specific death among 14,530 people with criminal convictions who had been prescribed methadone.
• Overall and cause-specific mortality rates were compared between periods when methadone was and was not dispensed.
• Periods when methadone was dispensed were associated with lower risk of mortality, including overdose fatalities, after controlling for covariates.

What do these findings mean?
• Practices to increase methadone adherence among opioid-dependent offenders are required and may reduce overdose-related, as well as other causes of, premature death.