Comparative treatment effectiveness. Effects of program modality and client drug dependence history on drug use reduction.

This study examined treatment outcome as a function of program modality, clients' lifetime patterns of drug dependence, and their interaction, controlling for current level of drug use at treatment intake. Data were based on 2,966 clients who were interviewed at intake and at 1-year follow-up as part of the Drug Abuse Treatment Outcome Study (DATOS), which included programs of four major modalities. Subjects' lifetime patterns of drug dependence were classified into nine groups according to Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R; American Psychiatric Association; 1987) diagnostic criteria and time of onset of drug use career. Outcome measure was the reduction of heroin use or cocaine use at follow-up from levels at intake. The results showed that rates of lifetime drug dependence and current drug use at DATOS admission were highest among methadone maintenance clients and lowest among outpatient drug-free clients. Drug use reduction was observed for all modalities. The presence of dependence diagnosis was associated with less improvement when current use level at intake was controlled. Clients dependent on heroin but not currently daily users benefited most from inpatient and residential programs. Methadone programs were also relatively ineffective in reducing cocaine use. Characteristics of the client's drug dependence history, in addition to the current or presenting drug problem, should be assessed to guide treatment planning. The high rate of cocaine dependence among methadone clients, most of whom were dependent on heroin, poses considerable challenge to contemporary opiate substitution treatments.