Aims-To examine whether need-service matching in addiction treatment leads to improvements in drug use, and whether treatment duration mediates those improvements.Design, participants, measurements-This analysis utilizes prospective data from a US cohort of addiction treatment patients who reported service needs beyond core rehabilitative services (n = 3103). 'Drug use improvement' is the difference between the patient's peak drug use frequency (in days per month) in the year before intake and in the year after treatment. Overall and primary use of the major illicit drugs (heroin, powder or crack cocaine and marijuana) are considered separately. 'Need-service match' means that a patient rated a service as important at intake and reported its receipt during treatment. 'Percentage of needs matched' indicates the proportion of five service domains (medical, mental health, family, vocational and housing) so matched.Findings-In mixed regression models controlling for multiple factors, a greater percentage of needs matched tended to improve primary (β = 0.028, P = 0.09) and overall (β = 0.049, P = 0.05) drug use in the follow-up year. Exclusion of treatment duration as a covariate doubled the magnitude of these coefficients. The benefits of matching were concentrated among the half of patients reporting needs in four to five rather than one to three domains, and were strongest among patients in longterm residential facilities. Addressing vocational and housing needs exerted the greatest effects.Conclusions-Matching comprehensive services to needs is a useful addiction treatment practice, especially for high-need patients. Treatment duration might partially mediate its effect.

OBJECTIVE:To examine whether the availability of primary medical care on-site at addiction treatment programs or offsite by referral improves patients' addiction severity and medical outcomes, compared to programs that offer no primary care.DESIGN: Secondary analysis of a prospective cohort study of patients admitted to a purposive national sample of substance abuse treatment programs.SETTING: Substance abuse treatment programs in major U.S. metropolitan areas eligible for demonstration grant funding from the federal Substance Abuse and Mental Health Services Administration.RESPONDENTS: Administrators at 52 substance abuse treatment programs, and 2,878 of their patients who completed treatment intake, discharge, and follow-up interviews. MEASUREMENTS:Program administrators reported whether the program had primary medical care available on-site, only off-site, or not at all. Patients responded to multiple questions regarding their addiction and medical status in intake and 12-month follow-up interviews. These items were combined into multi-item composite scores of addiction and medical severity. The addiction severity score includes items measuring alcohol and drug use, employment, illegal activities, legal supervision, family and other social support, housing, physical conditions, and psychiatric status. The medical severity score includes measures of perceived health, functional limitations, and comorbid physical conditions. MAIN RESULTS: After controlling for treatment modality, geographic region, and multiple patient-level characteristics, patients who attended programs with on-site primary medical care experienced significantly less addiction severity at 12-month follow-up (regression coefficient, À25.9; 95% confidence interval [95% CI], À43.2 to À8.5), compared with patients who attended programs with no primary medical care. However, on-site care did not significantly influence medical severity at follow-up (coefficient, À0.28; 95% CI, À0.69 to 0.14). Referral to off-site primary care exerted no detectable effects on either addiction severity (coefficient, À9.0; 95% CI, À26.5 to 8.5) or medical severity (coefficient, À0.03; 95% CI, À0.37 to 0.44). CONCLUSIONS:On-site primary medical care improves substance abuse treatment patients' addiction-related outcomes, but not necessarily their health-related outcomes. Further study is needed to discern the mechanism through which on-site primary care might improve the addictionrelated outcomes of substance abuse treatment.KEY WORDS: delivery of health care, integrated; outcome and process assessment (health care); primary health care; substance abuse treatment centers; substance-related disorders.

These findings suggest that for some treatment modalities, stronger primary care linkage mechanisms decrease subsequent utilization of expensive ED and hospital services. Future study should examine the cost implications of these strong linkage mechanisms and ways to strengthen linkages to off-site medical care.