Predictors of methadone maintenance treatment outcome have not been extensively studied as they relate to variations in program philosophy, nor have such predictors received much examination among recently treated, older cohorts of opioid addicts for whom drug use patterns have changed. Predictors of outcome were examined at 18 months post-treatment entry for 353 admissions to methadone maintenance who received random assignment to one of three counseling conditions: (1) medication only, (2) standard counseling and (3) enhanced services; and one of two contingency conditions: (1) no contingencies, and (2) contingency contracting in a six-cell 3 x 2 design. Subjects in contingency contracting conditions were placed on contingency contracts for positive urine toxicology results and ultimately discharged for unremitting drug use. All subjects completed the Addiction Severity Index (ASI) and provided weekly urine specimens. Predictors of urinalysis results and treatment retention were determined using bivariate and multivariate techniques. Interactions between subject characteristics by experimental condition assignment were also examined as predictors. Higher rates of total positive urine specimens were predicted by younger age, greater pre-treatment frequency of smoking cocaine, lower ASI psychiatric composite scores, and higher ASI legal composite scores. Higher rates of opiate positive specimens were predicted by younger age, lower pre-treatment frequency of alcohol intoxication, higher ASI legal and lower ASI employment and psychiatric composite scores, and assignment to medication only/no contingencies condition. Higher rates of cocaine positives were predicted by younger age, black race, lower ASI psychiatric composite score, greater pre-treatment frequency of intravenous and smoked cocaine use, less pre-treatment frequency of marijuana use, and lower methadone dose level. Assignment to enhanced/contingency contracting predicted lower rates of cocaine positives. Treatment retention was predicted by older age, non-black race, lower ASI legal composite score, higher methadone dose level and assignment to non-contingent conditions. While subject variables over which treatment providers have little control were, thus, related to outcome, type of treatment provided and methadone dose also influenced outcome.

Two commonly prescribed treatments for opioid addiction are methadone and buprenorphine. While these drugs show some efficacy in treating opioid dependence, treatment response varies among individuals. It is likely that genetic factors play a role in determining treatment outcome. This study analyses the pharmacogenetic association of 6 polymorphisms in OPRD1, the gene encoding the delta-opioid receptor, on treatment outcome in 582 opioid addicted European Americans randomized to either methadone or buprenorphine/naloxone ((Suboxone®) over the course of a 24 week open-label clinical trial. Treatment outcome was assessed as the number of missed or opioid positive urine drug screens over the 24 weeks. In the total sample, no SNPs in OPRD1 were significantly associated with treatment outcome in either treatment arm. However, sex-specific analyses revealed 2 intronic SNPs (rs581111 and rs529520) that predicted treatment outcome in females treated with buprenorphine. Females with the AA or AG genotypes at rs581111 had significantly worse outcomes than those with the GG genotype when treated with buprenorphine (p=0.03, RR=1.67, 95% C.I.[1.06-2.1]). For rs529520, females with the AA genotype had a significantly worse outcome than those with the CC genotype when (p=0.006, RR=2.15, 95%C.I.[1.3-2.29]). No significant associations were detected in males. These findings suggest that rs581111 and rs52920 may be useful when considering treatment options for female opioid addicts, however confirmation in an independent sample is warranted.

Using AIDS Initial Assessment questionnaire (AIA) data from 353 injection drug users (IDUs) newly admitted to methadone maintenance (MM), three dimensions of injection risk behavior ("sharing with sexual partner," "sharing with others," and "new needle use") were identified. Among IDUs who continued to inject drugs at 1 year, men retained in treatment obtained lower scores on the "sharing with others" scale than men not retained, even when controlling for initial scale scores and injection frequency. Associations between retention in MM and changes in sexual risk were examined using two AIA measures of sexual risk behavior ("number of IDU sexual partners" and "relative frequency of protected vaginal intercourse"). Controlling for injection frequency, prior sexual risk, and age, there was no difference in sexual risk for men retained in treatment versus those not retained. Among women, those who stayed in MM for 1 year reported significantly fewer IDU partners.

To determine how the injecting behaviors of injection drug users (IDUs) change over time in the context of the epidemic of acquired immunodeficiency syndrome (AIDS) and what factors may be associated with such changes, a cohort of IDUs (n = 313) initially in treatment provided structured interviews regarding drug injecting behaviors. Repeat interviews in 18 months assessed behavior change in subjects who could be contacted for follow-up (n = 220, 70.3%). The study occurred in a state where sterile syringes can be purchased without prescription in drug stores. Injection drug use occurred for 180 (81.8%) of the 220 subjects in the 12 months prior to the initial interview but in only 121 (55.0%) in the 10 months prior to the follow-up interview (p < 0.0001). Similarly, sharing of equipment decreased from 63.1% to 31.8% (p < 0.0001). Sharing with multiple partners declined from 41.9% to 10.6% (p < 0.0001). Factors associated with ongoing risk included use of injected and non-injected psychoactive substances, less time in drug dependence treatment during follow-up interval, having a sexual partner who was an IDU and not using a drug store as the primary source of syringes. Factors associated with multiple-partner sharing included use of psychoactive substances, younger age and nonwhite race.

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