Inmates who are addicted to opioid drugs who continue to receive methadone maintenance treatment in prison are more likely to continue treatment once they are released, according to a new study.

The study of 223 Rhode Island inmates undergoing methadone maintenance treatment found more than 97 percent who continued treatment in prison went to a methadone clinic within a month of their release. In contrast, 71 percent of those whose treatment was phased out in prison went to a methadone clinic soon after their release, HealthDay reports. All of the prisoners were offered financial and logistical assistance for getting methadone treatment when they were released.

Almost 90 percent of people undergoing methadone maintenance treatment for opioid addiction are cut off from the medicine if they are imprisoned, the researchers said. In some states, including Rhode Island, prisoners undergo phased withdrawal. In many states, treatment stops as soon as a prisoner begins their sentence.

Writing in The Lancet, the researchers say methadone treatment saves lives, reduces drug-seeking behaviors and helps reduce the spread of hepatitis and HIV.

“What we are doing with methadone in our correctional system is we are systematically taking people off it,” study author Dr. Josiah Rich of Brown University said in a news release. “It’s the only medication that is summarily stopped upon incarceration. This study questioned that policy to find out what happens,” said Rich, who is also Director of the Center for Prisoner Health and Human Rights at The Miriam Hospital.

He said denying inmates methadone treatment could increase the risk they will turn to crime after they are released. “For most of these people, the very reason they are caught up in the criminal justice system is related to their addiction to begin with,” he noted.