This report assesses the experiences of clients who had contact with or received drug abuse treatment from programs of the Addiction Services Agency in New York City and the Narcotics Treatment Administration in Washington, D.C. during the early 1970's. To answer the questions of what happens to former clients once they leave drug treatment programs and how those varying programs affected that outcome, random samples were drawn of clients who had entered any of several types of drug treatment, but who left in five days or less. Questions focused on the two month periods preceding drug treatment, following drug treatment, and preceding the interview. In general, former clients experienced a reduction in drug taking, an increase in employment, and a decrease in arrests. The study concludes that presence and type of treatment and clients' backgrounds were unrelated to the large behavior change experienced by them. Explanations for the changes fall into three major categories: (1) change in community attitude and knowledge, (2) the selection of interview subjects and (3) reduction of the availability and purity of drugs. Data tables are included. (Author/FC)