It is important to note that standard statistical models for multivariable analysis and longitudinal analysis of dichotomous outcome variables are based on the odds ratio, and differences in abstinence and other categorical outcomes were described through odds ratios. Some of our outcomes had moderately high prevalence, and so these odds ratios will be further from the null than the corresponding relative risks. For example, reports an odds ratio and 95% CI of 2.89 (1.22, 6.84) for abstinence in the intervention vs. assessed control group. The corresponding relative risk and 95% CI is 2.05 (1.13, 3.70).
Reducing marijuana use at the critical developmental stage of adolescence may interrupt a trajectory that would otherwise lead to injury, illness, dependence, and other negative health and social effects associated with heavy marijuana consumption. This preliminary PED study suggests that a 20 minute motivational interviewing style of conversation with a peer educator at the time of a clinical visit to the ED could reduce marijuana consumption, increase abstinence and decrease days of use. We are encouraged by the worst case analysis presented in , which sustains an odds ratio greater than 2. In other studies in which we were able to investigate reasons for refusal to keep a follow-up appointment, many patients stated that they did not come in because their use was behind them, they had changed their lives, and they did not want to be associated with the label of user or past-user.18
We therefore think it is unlikely that all non-followed patients in this sample were still using, as we presumed for this worst-case analysis.
Although the intervention group in this preliminary study was more likely to be marijuana abstinent at 12 months or to report reduce marijuana consumption if they were not abstinent, we detected no impact of either abstinence or reduced consumption on consequences and risk behavior. An earlier ED study among adult cocaine and heroin users receiving a peer intervention also increased abstinence rates and reductions in drug use based on hair analysis, but did not measure risk behaviors or consequences.18
Among adolescents and young adults who were high risk drinkers, intervention at time of the ED visit shows mixed results, with reductions in alcohol consequences in one study (n=94)8
and in consumption in a second, larger study (n=198).10
The current investigation differed from these alcohol intervention studies in three ways: 1) it focused on marijuana, not alcohol; 2) the motivational intervention was delivered by slightly older peers, rather than by experienced Masters’ level counselors; and 3) it enrolled PED patients who presented for a range of medical conditions rather than only those who were admitted for intoxication or an alcohol-related injury.
In a community setting, researchers investigated the efficacy of a single session of motivational interviewing in reducing use of marijuana.11
Those using marijuana who received the intervention were approximately 3.5 times as likely to decide to stop or cut down on the use of marijuana compared to those who received the non-intervention “educational as usual” control condition, even after adjusting for baseline and other potential confounders. The mean frequency of marijuana use declined by 66% in the intervention group; by contrast, the control showed a 27% increase
of marijuana use. Notably, the intervention showed the most significant impact on those youth considered high risk: males, frequent cigarette smokers, recipients of government benefits, and those who were rated more psychosocially vulnerable. While the findings of our study are somewhat less dramatic, they do demonstrate a significant intervention effect, especially since the PED intervention was limited to 20 minutes compared to one hour in the McCambridge study cited above.
We believe that the PED presents a difficult environment in which to effect behavior change because of the challenges of working around time restraints, the primacy of patient flow, clinical staff priorities, and variations in acuity. Despite these barriers, the peer educators integrated well into the ED setting and were able to deliver a consistent intervention with excellent adherence to protocol. In the population that uses an inner-city PED, marijuana use is a norm and a difficult topic to broach, yet peers in this study were able to engage on this issue and negotiate successfully with accompanying parents to leave the room during interviewing so that the adolescent’s privacy and confidentiality could be protected.
This preliminary study was not powered to capture relatively rare events or control for potential confounders. Follow-on studies are indicated to investigate impact on substance associated injury, identify the most effective context for screening questions (direct, drug-focused or embedded in a more comprehensive health survey), conduct sub-analyses to elaborate the role of predictors and moderators (demographics, mental health status, and operator differences), and determine which intervention components are most effective at what level of severity.