"Substance abuse treatment is more cost-effective than prison or other punitive measures. The Washington State Institute for Public Policy (WSIPP) found that drug treatment conducted within the community is extremely beneficial in terms of cost, especially compared to prison. Every dollar spent on drug treatment in the community is estimated to return $18.52 in benefits to society."

Source

Justice Policy Institute, "Substance Abuse Treatment and Public Safety," (Washington, DC: January 2008), p. 2.
http://www.justicepolicy.org/…