Fazel et al. confirm a high prevalence of substance use disorders among correctional populations. While misguided (‘criminalization’) policies result in many individuals with substance use disorders ending up in correctional institutions, these provide unique opportunities for interventions. Unfortunately, their potential is hindered by both correctional system and culture specific challenges. Fazel et al., in their systematic review, confirm results of their previous work regarding substantially elevated substance use disorders among correctional populations 1. Before offering thoughts on the implications for interventions, we make a point on key—and ‘social justice’-focused—forces behind these data. That is, that there are multiple dynamics resulting in the incarceration of disproportionately large numbers of individuals with substance use disorders. Many such disorders result in criminogenic and punishable behavior (e.g. alcohol- or stimulant-related violence) 2, yet a substantial proportion of disorder-inflicted offenders are incarcerated because many control regimes still deal with substance use disorders (or their consequences, e.g. acquisitive crime) as primarily a criminal justice rather than a health issue. These regimes commonly fail to provide adequate supports and interventions for individuals with substance problems, with many ending up in prisons due to their problems as a ‘last repository’ 3, 4. Thus, interventions to reduce the prevalence of substance use disorders in correctional systems ought to include revision of these misguided policies, and instead prioritize health- and socially oriented responses. Conversely, correctional systems are—as paradoxical as this may appear—‘ideal’ places to initiate and provide treatment interventions for substance use disorders (as much as for other chronic diseases, e.g. infectious disease such as HIV or hepatitis infections), at least for longer-term inmates. Many such interventions have shown good or promising results 5. For substance use treatment, the availability of opioid maintenance (e.g. methadone-based) treatment has been expanded substantially in recent years and is associated with improved health, drug use and recidivism outcomes 6. Cognitive–behavioral, motivational and therapeutic community-based treatment programs, alongside self-help programs, have also demonstrated positive impacts 7. There are, however, multiple powerful factors hindering adequate availability and utilization of substance use treatment in correctional settings. These include the fact that correctional systems, in general, still tend to view substance use disorders as forms of moral deviance (or behavioral choices that are part or indicative of ‘criminal careers’) 8, 9. Consequently, correctional systems are commonly both laggards in implementing state-of-the-art interventions and also hesitant to ‘reward’ inmates with substance use problems by providing them with special services and attention 9, 10. Then, there are structural barriers; for example, that specialized expertise or services are commonly not available in sufficient supply due to a lack of material or skilled staffing resources 9, 11. There are also ‘soft factors’ such as stigma or fear of repercussions that make offenders hesitant to come forward and identify substance use issues and actively seek and utilize supports as this may also reveal current behaviors violating institutional codes of conduct 5, 8, 10. There have been laudable select ideas and efforts to address some of these barriers, yet they are unlikely to be sufficient, as most of the barriers are systemic or structurally driven from within the distinct institutional realm of ‘corrections’. Importantly, treatment for substance use disorders among correctional inmates cannot be viewed in exclusive isolation vis-à-vis the wider contexts of correctional institutions. The large majority of inmates will be released eventually into the community. As such, when involving chronic conditions such as substance use disorders, effective and seamless transition of treatment and other care from the institution to outside settings upon release to the community is crucial 12. This, however, fails critically in many instances and constitutes the ‘Achilles heel’ of substance use disorder care for many correctional offenders 9, 13, 14. International data demonstrate powerfully that offenders are at highest risk for relapsing to substance abuse and succumbing to acute harms, including drug overdoses, in the immediate short period post-release 15, 16. Many offenders upon release feel lost in the ‘outside world’, do not have adequate social or health-care plans or arrangements in place and commonly return to old (deviant) environments or networks as well as substance use habits 14, 17. These adverse dynamics are particularly pronounced, and difficult to address, in offenders with short-term sentences or stays in correctional systems, commonly rotating in and out of institutions 6, 18. Select efforts to address these challenges have been made, with some successes, yet these are limited and highly resource-intensive (e.g. case management) 11, 19. Overall, the phenomenon of substance use disorders in corrections represents a convergence of several major problems—the organization of corrections, failed substance use control policies, care provision to marginalized populations and corrections-based interventions limited in reach and effectiveness. This convergence of these major challenges requires more and broader action than simply better substance use disorder programming within correctional walls. B.F. acknowledges funding from Canadian Institutes of Health Research (CIHR) for the Ontario CRISM Node Team (grant no. SMN-139150), which supported parts of the present study. None.