Services Research Outcomes Study (SROS)

FINDINGS

INTRODUCTION

Scientific research on the outcomes of treatment programs for drug abuse, drug dependence, and related problems (more concisely, drug treatment) date back at least to the 1920s, when in the aftermath of the Harrison Narcotic Act of 1914, morphine maintenance clinics were established by physicians in a number of U.S. cities. These clinics were meant to serve individuals addicted to opiates, whose previous supply sources were closed by enforcement but who were unable or unwilling to remain opiate-free. Studies of clients in these clinics were the first in an irregular series of studies, dating from the 1930s through the early 1960s, in which the clients of one or a small number of treatment facilities were followed up at brief intervals after admission to learn about the results of treatment. Such studies became much more common after the early 1960s.

Single-site, short-term studies can provide useful evidence about the potential efficacy of drug treatment as an available instrument of drug control policy—that is, whether an intervention with a selected population of impaired drug users can reduce their level of continued abuse and dependence. Such studies do not go very far, however, toward answering the most salient and immediate policy questions about treatment, such as how much the treatment costs, how many clients it reaches, what overall level of effectiveness it has, and what directions can be taken to improve the overall performance of the system. These are simple questions to phrase, but the effort to find clear and accurate answers to them has proven to be a complex undertaking. The sheer diversity and scale of the national treatment system, with one million or more clients each year who present every type of drug problem and receive multiple types of treatment in more than 10,000 facilities, defy easy characterization. Moreover, the character of drug problems and the tendency of these problems to change characteristically over time present serious obstacles to the precise calculation of a simple, meaningful "success rate." Instead, an understanding of how and how well treatment works requires a steady accumulation and cross-checking of findings from many sites, ideally chosen to reflect accurately the many facets of the treatment system and clients seen within it.

The Services Research Outcomes Study (SROS) is the most recently completed in a series of large, multisite, national followup studies developed by Federal agencies and their research partners since the late 1960s to address the overarching policy questions about drug treatment. The first study of this type was the Drug Abuse Reporting Program (DARP). This study set the agenda in many ways for studies to follow. The DARP staff collected systematic data at admission and at regular intervals during treatment from nearly 44,000 clients in 52 federally funded treatment facilities in 24 States between 1969 and 1973. The DARP investigators referred to this client population as "a highly representative sampling of opiate addicts, drug abusers, and treatment approaches observable in the United States during the four-year period covered" (Sells, 1974); however, the rapidly expanding nature of the treatment system and the lack of any relevant national sampling frames (for treatment facilities, clients, or users) at the time make this a difficult claim to evaluate.

The original DARP study collected a great deal of data from clients at admission and during treatment on drug and alcohol use; criminal involvement; employment; and social, psychological, and physical status and functioning. However, the study collected no information about post-treatment outcomes. Subsequently, the DARP staff followed up a stratified random sample of clients from 25 facilities approximately six years after treatment and completed 3,100 multidimensional interviews from the 4,100 clients sampled, for a 76-percent completion rate. A further stratified subsample from the six-year followup group, composed of clients who had been daily opioid users at the time of admission to 18 of the facilities, was followed up again 12 years after treatment by the same DARP team, who completed 500 interviews from a sample of 700, for a 70-percent completion rate. (In addition, in the intervening six years, 52 deaths were recorded.)

The DARP studies provided a model for using repeated multidimensional interview responses to assess treatment outcomes and a long-term timeframe to permit the measurement of behavior across an extended "treatment career." Three major multisite national outcome studies have been conducted since DARP, but no other, to this point, has used such an extended timeframe. These studies are the Treatment Outcomes Prospective Study (TOPS), which included a three-year followup of individuals admitted to treatment during 1979–1981; the Drug Abuse Treatment Outcomes Study (DATOS), covering a 1991–1993 admission cohort, for which a one-year followup has been completed to date; and the National Treatment Improvement Evaluation Study (NTIES), covering a 1993–1994 admission cohort, for which a one-year followup study has been completed. Although each of these studies was national in scope, each began with a purposive sample rather than a systematic probability sample of treatment facilities. Both TOPS and DARP selected ten large cities (the same city in seven of ten instances), and staff from each study successfully recruited a handful of programs in each city to participate. The NTIES staff, in contrast, began with a pool of hundreds of facilities, located in nearly every U.S. State and territory, that were participating in 1990–1991 demonstration grant programs of the Center for Substance Abuse Treatment. All of the recipient facilities were recruited by the NTIES staff to provide facility-level information on services, staffing, and costs; about one in ten of these facilities was then purposively selected for inclusion in the largest client followup study to date.

Alone among the studies cited, SROS began with an enumerated national listing composed of more than 10,000 facilities known to provide drug services; the study then used stagewise stratified random sampling to select facilities and clients. Thus, the current report is able to weight every participant in the study to represent an appropriate number of clients in the original sampling frame and therefore estimate characteristics and outcomes that are statistically representative of treatment clients in the United States as a whole during a five-year followup interval. Although the loss of facilities and clients in the sample at each stage, beginning with Drug Services Research Survey (DSRS), introduces uncertainty and possible bias into these estimates, as discussed in Chapter II and Appendix A, these results come closer than those of any previous study to providing a detailed, national population-based profile of drug abuse treatment outcomes.

Based on the systematic multistage probability sample described in Chapter II (and detailed further in Appendix A), the data presented in this chapter represent an estimated population of approximately 967,000 [ This estimate is rounded to the nearest thousand, and this notation continues throughout the text.] clients who were discharged from treatment at least once between September 1, 1989, and August 31, 1990. From a sample of 3,047 clients drawn from program records, this chapter reports on data from the 1,799 clients followed up and interviewed during 1995 and 1996, an average of 5.5 years after treatment, and analyzes abstracted data from clinical records on the 277 clients determined to have died between treatment discharge and followup, who represent an additional estimated population of 93,000 clients discharged from substance abuse treatment during 1989–1990.

This chapter is separated into four major sections. The first two sections characterize the two major component elements of the study: First, the SROS sample of treatment facilities as they functioned in 1990 and in subsequent years, and second, estimates of the characteristics of all the clients in the sample before and during their treatment episodes in 1989–1990. The chapter then analyzes changes in client behavior and circumstances in the five years before and after treatment, assessing differences along each of the major domains (drug and alcohol use, criminal activity, health, and social functioning) for the client population as a whole and among distinct subgroups. This third section includes statistical analyses (using multiple regression techniques) of particular correlates of change in behavior and circumstances, providing statistical evidence on the association between treatment and five-year outcomes. The final section analyzes data on mortality during the followup period, comparing estimated death rates among the 1989–1990 client population with those of the general population and using multiple regression techniques to explore the correlates of mortality among the client population.

This page was last updated on June 03, 2008.

SAMHSA, an agency in the Department of Health and Human Services, is the Federal Government's lead agency for improving the quality and availability of substance abuse prevention, addiction treatment, and mental health services in the United States.