Sending substance-abusing state prisoners to community-based treatment programs instead of prisons could reduce crime and save billions of dollars, a new study concludes. The savings would result from immediate reductions in the cost of incarceration, and by subsequent reductions in the number of crimes committed by successfully treated offenders, which leads to fewer re-arrests and re-incarcerations, according to the researchers.

Almost half of all state prisoners abuse drugs or are drug-dependent, but only 10 percent received medically based drug treatment while they are incarcerated, according to Newswise. Inmates who are untreated or not adequately treated are more likely to start using drugs when they are released from prison, and commit crimes at a higher rate than those who do not abuse drugs, the article notes.

The researchers built a simulation model of 1.14 million state prisoners, representing the 2004 U.S. state prison population. The model estimated the benefits of substance abuse treatment over individuals’ lifetimes, and calculated the crime and criminal justice costs related to policing, trial and sentencing, and incarceration.

The model tracked individuals’ substance abuse, criminal activity, employment and health care use until death or until they reached age 60, whichever came first. They estimated the costs of sending 10 percent or 40 percent of drug-abusing inmates to community-based substance abuse treatment instead of prison.

In the journal Crime & Delinquency, the researchers found that if just 10 percent of eligible offenders were treated in community-based programs instead of going to prison, the criminal justice system would save $4.8 billion, compared with current practices. If 40 percent of eligible offenders received treatment, the savings would total $12.9 billion.