Prior research had shown that alcohol and drug abuse treatments were effective and that the results of treatments could be predicted from pretreatment information regarding the patient's employment, family, and especially psychiatric problems. However, this research had been conducted entirely with adult male service veterans, largely from lower socioeconomic strata. Three treatment centers were included in the present study to examine these conclusions with other populations containing adolescents, females, and patients from higher socioeconomic strata. Data from the Addiction Severity Index was collected at treatment admission and again at independent follow-up, 6 months later. Results confirmed prior observations. Both alcohol and drug abuse treatments showed substantial improvements in the chemical use problems of their patients and in the important areas of employment, criminal behavior, family relations, and psychological health. As in earlier reports, a global measure of the nature and extent of pretreatment psychiatric problems was the single best predictor of treatment response for both alcoholics and drug-dependent samples.