One of the main ways to end a destructive addiction to opium class drugs like heroin is to get methadone treatment, which prevents withdrawal but doesn't provide the same high. But, the predominant policy in the American criminal justice system is to immediately cut off methadone treatment for people who are receiving it, or to do so in a quick phase out.
A new study in Rhode Island confirms that this policy is a bad one. Cutting someone off from methadone while incarcerated dramatically reduces the chances that they'll keep trying to quit when they get out. It also greatly increases the chance that they'll suffer a heroin overdose when they return to using a drug they've lost tolerance to at the doses they used to use. Reduced post-incarceration ER costs alone more than outweigh the cost of providing methadone to inmates.
Methadone treatment is also highly effective, reducing the death rates of people in treatment relative to those who remain addicted by 70%.
Also, the knowledge that methadone treatment (which is harder to withdraw from than heroin use itself) will be withdrawn if you are incarcerated, reduces the number of people who try to get off heroin using the treatment.
In addition to all of this, the painful withdrawal symptoms associated with stopping methadone treatment are themselves a form of punishment often inflicted on people incarcerated while awaiting trial, and a form of coercion to force inappropriate guilty pleas for criminal defendants receiving methadone treatment (who are, of course, the ones who are at least trying to fix themselves).
The policy of withdrawing methadone treatment immediately, or phasing it out, for incarcerated individuals is wrong in pretty much every respect and should be reversed immediately.