This paper reviews a serious of U.S. cost-benefit studies for alcohol and substance abuse treatment.  The study concludes that untreated drug and alcohol addicts incur costs and use health care at a rate twice as high as their peers.  After initiating treatment, health care utilization and costs drop, eventually reaching a level below pre-treatment conditions on average 2 to 4 years later.  Though there are no gender differences in the effectiveness of treatment there are age differences that highlight the value of early intervention. The study gives detailed results for drugs and alcohol separately.

Holder, H. D. (1998). Cost benefits of substance abuse treatment: an overview of results from alcohol and drug abuse. Journal of Mental Health Policy and Economics, 1(1): 23-29. http://www.icmpe.org/test1/journal/issues/v1i1/v1i1abs04.html 

Author: Harold D. Holder