The report said roughly 70 percent of those held in U.S. jails and prisons are drug-addicted, compared to 8 percent of the general population. Most convicted criminals say they have been drug or alcohol abusers and half report they were high when committing their crimes.

Even after years of abstinence in prison -- an unlikely prospect, given the prevalence of illegal drugs in these institutions -- addicted inmates are more than likely to relapse after their release from prison and return to crime, Nora Volkow, director of the National Institute on Drug Abuse, said in an interview with Reuters. Some 650,000 prisoners are released back into society each year.

CUTTING RECIDIVISM

The agency's report, which Volkow said is aimed at influencing those running and funding the criminal justice system, said drug treatment of addicted prisoners could cut their recidivism rate by at least half, compared to the two-thirds of untreated inmates who commit new crimes and are arrested.

For every dollar spent on drug treatment in prisons and jails, the savings from less crime and abuse amount to between $4 and $7, the report estimated.

An effective drug treatment program of at least 90 days costs between $14,000 and $17,000 per inmate, Volkow said.

Volkow said the studies emphasize the importance of an after-care program. Even if a released inmate has had a good response to substance abuse treatment in prison, the stress of everyday life -- such as lack of a job or profession, no family support -- can lead them back to addiction.

A pilot program in Chicago emphasizes "drug courts" where abusers are routinely offered the choice of monitored treatment and counseling in lieu of a prison sentence. Twenty criminal court judges were taught the latest science into the biological impacts of drug use.

"Relapse is part of the disease," said Timothy Evans, the chief judge in Cook County, which comprises Chicago. His judges wield drug treatment as an alternative to punishment, he said.

"There's always a waiting list" for treatment, however, said Melody Heaps, head of the leading counseling program in Illinois. "You can wait six weeks up to two months for people who want to get into treatment. Only 10 percent of people in Illinois are getting it that want it."

A similar treatment rate for diabetes or cancer would trigger outrage, she said.

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