As hypothesized, methadone maintenance participants were more likely to attend both HIV prevention interventions than psychosocial outpatient participants. However, contrary to our hypothesis, participants in psychosocial outpatient programs who completed the REMAS intervention reduced their unprotected sexual occasions more than participants in methadone programs who completed the REMAS intervention. At 6-months post intervention, the adjusted mean change for REMAS completers in psychosocial outpatients programs was nearly 3 times greater than that for the REMAS completers in methadone programs. Corresponding effect sizes were also robust (d = 0.38 versus d = 0.25). Thus, REMAS appears to be especially effective for individuals receiving substance abuse treatment in a psychosocial outpatient program. It should be noted, however, that the REMAS intervention was effective even for those who received it in a methadone program compared to participants who completed the 1-session HIV education intervention (the latter did not reduce their unprotected sexual occasions from baseline levels, in either methadone maintenance or psychosocial outpatient programs).
There are several possible factors that might explain the unexpected finding of superior effectiveness of REMAS in psychosocial outpatient programs compared to methadone programs. These factors include aspects of the study design, confounding patient variables between the treatment program types, the effects of methadone as a treatment, and greater relevance of the REMAS intervention to patients in psychosocial outpatients programs. The study design permitted psychosocial outpatients to enroll in the current HIV sexual risk reduction investigation at any point in their participation in their substance abuse treatment program, and methadone patients to enroll anytime past the initial 30 days of treatment. Previous studies have found attrition from psychosocial treatment programs is very high, while patients who initially engage at a methadone program typically continue in treatment.22
Data from the current study is consistent with this pattern; randomized participants in the psychosocial outpatient programs were significantly more likely than those from methadone programs to drop out of the treatment program before obtaining their first REMAS or HIV-Ed session. Increased dropout within psychosocial programs supports our hypothesis of superior intervention exposure in methadone maintenance programs. We can speculate that the desire for methadone likely promotes continued attendance in methadone programs, regardless of patients' overall level of motivation to participate in substance abuse treatment. In contrast, less motivated patients are likely to drop out of psychosocial outpatient programs early in the process, leaving a more motivated patient sample to participate in treatment and make improvements to their lives. This strengthened motivation may translate into greater skill attainment in the REMAS program, and consequently better outcomes.
Other patient variables may also be confounding the comparison of methadone programs with psychosocial outpatient programs. Patients participating in these programs differed at baseline on a host of demographic variables, (age, education, employment, race) and sexual risk variables (rates of engaging in vaginal intercourse, having high risk sexual partners, and engaging in sex under the influence of drugs or alcohol). However, even when these variables are statistically controlled in the data analysis, the psychosocial outpatient-methadone maintenance program differences remain. REMAS may also have been more effective in psychosocial outpatient programs because a greater percentage of patients in these programs found the content of REMAS to be more relevant to their sexual lives. Thus, it may be that more patients in the psychosocial treatment programs were better able to make use of the skills taught in REMAS in their daily lives.
The REMAS intervention consisted of five 90-minute group counseling sessions. The REMAS modules were more likely to be similar in both process style and content to the group counseling visits already provided to psychosocial outpatients in their treatment program. In contrast, REMAS modules may have seemed somewhat dissimilar to the treatment interventions to which methadone maintenance patients were familiar as most of the psychosocial treatment provided in those settings is via individual counseling. This difference in familiarity may have impacted REMAS effectiveness in the two settings.
Another possible reason for reduced effectiveness of REMAS in methadone programs is the pharmacological effect of methadone. Opiate dependent individuals receiving methadone have been found to show greater cognitive impairments than abstinent heroin abusers entering inpatient rehabilitation as measured by standardized neuropsychological tests.38
In addition methadone maintenance patients demonstrated impaired decision-making and slower cognitive flexibility than buprenorphine maintained patients and matched non-drug abusing controls on the Iowa Gambling Task and the Wisconsin Card Sorting Task.39
These methadone-induced cognitive impairments may interfere with learning of REMAS skills, and the impaired decision-making may result in higher rates of unprotected sex, compared to patients not receiving methadone (and less likely to be opiate dependent) in the psychosocial outpatient programs.40
To counter possible cognitive effects of methadone, the REMAS intervention may need to be modified in order to enhance effectiveness. Smaller groups, a slower pace, and extended numbers of sessions are possible modifications that could facilitate learning within this population. Further research into cognitive rehabilitation or remediation (e.g., Grohman and Fals-Stewart41
) to facilitate HIV prevention skill uptake should also be explored.42
In addition to the study limitations mentioned above (i.e., multiple confounding variables; impact of attrition from treatment programs on exposure to study interventions), several other limitations should be mentioned. Participants self-referred to the study. It is unknown how similar or different they were from other patients attending participating clinics who did not participate, thus somewhat limiting generalizability. Study participants may have been more or less motivated to change their sexual risk behavior compared with non-participants. Whatever the impact of self referral might have been on the parent study, we have no reason to believe that self referral differed as a function of treatment modality. It is important to acknowledge that the comparison between methadone programs and psychosocial outpatient programs was a secondary aim of the study evaluating the effectiveness of REMAS. The results presented here need to be confirmed with a prospective study that is designed, and statistically powered, to evaluate differences in effectiveness between program modalities. Another limitation is that it is difficult to attribute with any certainty the differences between REMAS and the 1-session HIV education intervention to the specific content of the REMAS model. Because REMAS was 5 sessions, any differences between these interventions may have been due to the duration, rather than the content, of the interventions. A final limitation relates to our ability to extrapolate the current findings to the clinical implementation of REMAS in drug treatment programs. In our study, participants were provided with modest financial incentives to encourage attendance in the intervention groups. These financial incentives may have increased attendance, and we highlighted results that emerged from the sample of participants who completed the interventions. Most drug treatment programs do not provide financial incentives to patients and therefore in clinical practice fewer patients might be expected to complete, and therefore benefit from, such interventions if attendance is voluntary.
In summary, a 5-session sexual risk reduction intervention for men involving didactically-delivered informational material, role-plays, peer group discussions, and self-assessment motivational exercises was found to have superior effectiveness in reducing unprotected sexual occasions, compared to a 1-session HIV education intervention, among patients in psychosocial outpatient substance abuse treatment programs compared to patients in methadone programs. Modifications of the REMAS approach may be needed to further enhance effectiveness with methadone maintained patients.