Sentence Reduction While In Prison

Residential Drug Abuse Treatment Program (RDAP) is a nine-month program with about 500 hours of cognitive treatment that includes inpatient and community placement for inmates with a diagnosed and documented substance abuse.  RDAP is the only BOP program through which federal prisoners can earn a sentence reduction.
Defendants may hesitate to mention their history of substance abuse to their probation officers during pre-sentence interviews because of fear this may impact any cooperation credit defendants seek in the course of a plea bargain.
 
Depending on the facts and circumstances of the case, if a defendant wishes to receive cooperation credit and participate in a RDAP program where they receive reduced custody time for drug education and rehabilitation, reference to substance abuse history must be mentioned in a verifiable document, typically the pre-sentence investigation report (PSI). Otherwise, the Court will not order probation to amend their report to reflect a drug problem and the Bureau of Prisons will be unable to unable refer the individual to RDAP without a record of substance abuse for a period of 12 months preceding the arrest. It is better that a presentence investigation report refers to a substance abuse history than not. But again, this depends on whether the person would be eligible for RDAP in the first place.
 
To be eligible for RDAP an inmate must have at least two years of his/her prison term remaining, and a documented pattern of substance abuse the year immediately prior to arrest.  Mentally impaired inmates cannot participate in RDAP, and the RDAP candidate cannot be a deportable non-U.S. citizen as this also makes them ineligible for halfway house. 
Pursuant to 18 U.S.C. Section 3621(e), offenders who successfully complete the RDAP program while in custody are eligible for release up to one year before the expiration of sentence. This is the only BOP program that allows federal prisoners to get their sentence reduced.
Only certain federal correctional institutions have the RDAP program. Moreover, although certain sex offenders are not automatically disqualified from RDAP, an offense involving sexual abuse of minors, does.