"Increases in admissions to substance abuse treatment are associated with reductions in crime rates. Admissions to drug treatment increased 37.4 percent and federal spending on drug treatment increased 14.6 percent from 1995 to 2005. During the same period, violent crime fell 31.5 percent. Maryland experienced decreases in crime when jurisdictions increased the number of people sent to drug treatment."
Justice Policy Institute, "Substance Abuse Treatment and Public Safety," Washington, DC: January 2008.