Alcohol and marijuana are the most common substances of abuse among adolescents. Overall, Healthy Choices appears to reduce alcohol use among YLH. By the 15-month follow-up, only 37.9% of the intervention group reported using alcohol in the past week, whereas 53.6% of the control group reported use. More importantly, this MI-based intervention was effective over time in reducing the adolescent's probability of being a high-risk drinker, with the intervention significantly reducing the likelihood for an adolescent to be classified into the high-risk trajectory group. In previous studies, MI was found to be more effective for reducing heavy drinking among patients with mild to moderate alcohol dependence than a feedback/education session or multiple sessions of nondirective reflective listening.19
Similarly, in this study the intervention appeared to have the largest effect on the high-risk drinking group.
The intervention had what would appear to be a clinically significant—as well as statistically significant—effect for alcohol use. However, there was a reduction of marijuana use only for low and moderate users. Again, this corresponds to previous studies that have shown MI to be more effective in reducing substance use among the at-risk or mildly dependent, rather than for more severely dependent persons.20
Reducing HIV-positive adolescents' alcohol use may also have beneficial effect on their medication adherence. Lower alcohol use has been associated with medication adherence among HIV-infected adolescents.21
Moreover, it may also have beneficial effects on other health behaviors, as substance use plays a significant role in high-risk sexual behavior.22
However, it also appears that the benefits of MI for substance-using youth may take some time to take effect, as the significant differences between the trajectory groups became more apparent over time. Although the majority of studies of MI show that effects emerge relatively quickly,23
the notion of a delayed effect is consistent with some previous findings. For example, in one study motivational therapy (in conjunction with contingency management) had the highest rates of success at later follow-ups.24
Similarly, another study of MI for college students showed a “sleeper effect,” in which the strongest effects were identified at 15-months after brief intervention.25
The effects of Healthy Choices appear to vary based on frequency of alcohol and marijuana use/group membership, and thus may be hard to determine without conducting trajectory analyses. This may account in some cases for previous discrepant findings about the efficacy of this type of intervention for youth.12
However, MI interventions for YLH show some promise in reducing alcohol and marijuana use risk—one of many risk behaviors engaged in by this population—and studies to replicate these secondary analyses should be conducted.
There are a number of limitations to this study. We compared a four-session intervention plus standard care to standard care alone, and thus we did not match for time. However, these limitations are somewhat offset by the fact that the number of sites is a strength of the study, as was the centralized supervision. Another limitation was that the study relied on self-reported substance use, and could be subject to social desirability influences. In addition, the sample size was fairly small, and was primarily African American (78.3%). Analyses were conducted to determine if race/ethnicity or gender orientation had any effect in changing the results, and their inclusion had no effect. However, this would be better investigated in a larger study that includes a higher proportion of non-African American youth. Finally, results need to be confirmed, and with larger sample sizes of HIV-positive substance using youth so that other factors (e.g., different developmental age ranges, ethnicity) can be investigated.