Motivational Interviewing to Reduce Alcohol Use in Youth
Motivational Interviewing to Reduce Alcohol Use in Youth
To our knowledge, this is the first systematic review and meta-analysis on the efficacy of emergency care triggered brief interventions that include MI to reduce risky drinking behaviour in young people. The included trials not only studied alcohol consumption, but also alcohol-related risks and problems. Our focus was on alcohol consumption as the outcome most comparable across trials. While four trials found MI more successful than control interventions in reducing alcohol-related consequences (Monti et al., 1999, 2007; Cunningham et al., 2009; Bernstein et al., 2010), there was less evidence for an additional impact of MI in emergency care brief interventions when it comes to alcohol use.
One study found no change in alcohol use after either intervention (Bernstein et al., 2010). Young people reduced their alcohol consumption in some way after an alcohol-related emergency care contact in five out of six RCTs, regardless of the content of the brief intervention (Monti et al., 1999, 2007; Spirito et al., 2004; Cunningham et al., 2009; Segatto et al., 2011). There is, however, debate that alcohol consumption may not be reduced as an effect of an intervention, but rather due to regression to the mean or behavioural change resulting from screening (see, e.g. Finney, 2008; Jenkins et al., 2009). The impact of such forces other than the intervention may be mitigated to some extent when differences between randomized groups are assessed. MI contributed to the reduction in alcohol consumption significantly in two studies (P < 0.05) (Spirito et al., 2004; Monti et al., 2007); of which one described a significant additional impact of MI only for the subgroup of more heavy drinkers (Spirito et al., 2004).
Investigating the raw data extracted from the original studies, drinking frequency and/or quantity increased again after an initial decrease in one or both intervention groups in some trials, but usually remained below the preintervention level by the end of study period (Monti et al., 1999, 2007; Spirito et al., 2004; Cunningham et al., 2009). In one of the trials, the control group's drinking frequency after 1 year even appears to have surpassed its baseline level (Spirito et al., 2004). No relapse in alcohol use, but the increase in drinking quantity between 3 and 12 months in the Spirito et al. (2004) trial (P < 0.04), was statistically significant although the phenomenon of reraising average consumption levels occurred frequently in the trials reviewed.
The meta-analysis suggests that MI-based interventions are at least as effective as control interventions and have potential to be more effective. We conducted separate meta-analyses for the correlated drinking frequency and drinking quantity outcomes, as well as for one more, and one less heterogeneous set of trials. Based on the largest effect size differences, the frequency of drinking was reduced significantly more by MI than other brief interventions, regardless of whether we studied US trials on their own or together with a trial from Brazil (SMD ≤ −0.17, P ≤ 0.03). Further meta-analyses indicated no significant SMD in the drinking quantity for all trials (SMD = −0.09, P = 0.18). Within the US trials only, a significantly lower amount of alcohol was consumed after a MI intervention (SMD = −0.12, P = 0.04). Meta-analyses based on the smallest differences in the effect size found no differences in the alcohol consumption after intervention between groups (SMD ≤ 0.02, P ≥ 0.38).
The Brazilian trial differed in several aspects from the US trials in the sample beyond its cultural setting: The experimental intervention was implemented solely by one researcher. The trial relied exclusively on self-report in evaluating the intervention effects, and with only one follow-up after 3 months it was the shortest trial in the sample. The sample was composed of ~40% of alcohol dependents in each group. This portion could be higher than in the other trials studied because brief interventions usually target risk populations at an early stage of alcohol-related problems (Segatto et al., 2011). In addition, risks associated with alcohol abuse, which may correlate with the readiness to change alcohol consumption, were not balanced at baseline and no intention-to-treat analysis was performed. Despite these differences between trials, results from the meta-analyses with and without the Brazilian trial suggested that some additional reduction in alcohol consumption can potentially be achieved by MI.
Our review and meta-analysis are subject to limitations. The methodological quality of the studies included ranges from poor to good. The major concern with respect to the quality of the meta-analyses, which were based on unadjusted raw data, is the high numbers of dropouts of at least 6.6%, and up to 30.6% of participants. These dropout rates are likely to have introduced a substantial but unexamined bias. Publication bias was indicated for the selective study of drinking frequency outcomes from US trials with the strongest MI effects. Confirming an additional impact of MI on the drinking frequency in the meta-analysis of the USA and Brazil trials, for which a possible publication bias was not indicated, mitigates our concern that estimating a positive upper bound for an additional effect of MI in emergency care brief interventions may be a result caused by publication bias. Within the original studies, few included dropouts in their final assessment (Cunningham et al., 2009) or made a sensitive analysis to investigate the worst-case situation of equating loss to follow-up with a negative answer for change attempts, at least for alcohol-related consequences (Bernstein et al., 2010).
No reviewed study states whether MI was adapted to the special needs and demands of young people as discussed, for instance, by Gillian (1991). Combined interventions, like MI plus normative resetting and skills training or MI plus 'booster' phone calls, were tested in some studies (Monti et al., 2007; Cunningham et al., 2009; Bernstein et al., 2010), preventing us from deducing the efficacy of MI on its own. The methodological differences in the analyses and interventions limit the comparability of the study findings reviewed. Finally, we did not study alcohol-related problems as an outcome. However, it is often a history of alcohol-related problems that brings a patient to the attention of a medical provider, and the reduction of these problems rather than alcohol consumption itself might be the aim of an opportunistic brief intervention.
Discussion
To our knowledge, this is the first systematic review and meta-analysis on the efficacy of emergency care triggered brief interventions that include MI to reduce risky drinking behaviour in young people. The included trials not only studied alcohol consumption, but also alcohol-related risks and problems. Our focus was on alcohol consumption as the outcome most comparable across trials. While four trials found MI more successful than control interventions in reducing alcohol-related consequences (Monti et al., 1999, 2007; Cunningham et al., 2009; Bernstein et al., 2010), there was less evidence for an additional impact of MI in emergency care brief interventions when it comes to alcohol use.
One study found no change in alcohol use after either intervention (Bernstein et al., 2010). Young people reduced their alcohol consumption in some way after an alcohol-related emergency care contact in five out of six RCTs, regardless of the content of the brief intervention (Monti et al., 1999, 2007; Spirito et al., 2004; Cunningham et al., 2009; Segatto et al., 2011). There is, however, debate that alcohol consumption may not be reduced as an effect of an intervention, but rather due to regression to the mean or behavioural change resulting from screening (see, e.g. Finney, 2008; Jenkins et al., 2009). The impact of such forces other than the intervention may be mitigated to some extent when differences between randomized groups are assessed. MI contributed to the reduction in alcohol consumption significantly in two studies (P < 0.05) (Spirito et al., 2004; Monti et al., 2007); of which one described a significant additional impact of MI only for the subgroup of more heavy drinkers (Spirito et al., 2004).
Investigating the raw data extracted from the original studies, drinking frequency and/or quantity increased again after an initial decrease in one or both intervention groups in some trials, but usually remained below the preintervention level by the end of study period (Monti et al., 1999, 2007; Spirito et al., 2004; Cunningham et al., 2009). In one of the trials, the control group's drinking frequency after 1 year even appears to have surpassed its baseline level (Spirito et al., 2004). No relapse in alcohol use, but the increase in drinking quantity between 3 and 12 months in the Spirito et al. (2004) trial (P < 0.04), was statistically significant although the phenomenon of reraising average consumption levels occurred frequently in the trials reviewed.
The meta-analysis suggests that MI-based interventions are at least as effective as control interventions and have potential to be more effective. We conducted separate meta-analyses for the correlated drinking frequency and drinking quantity outcomes, as well as for one more, and one less heterogeneous set of trials. Based on the largest effect size differences, the frequency of drinking was reduced significantly more by MI than other brief interventions, regardless of whether we studied US trials on their own or together with a trial from Brazil (SMD ≤ −0.17, P ≤ 0.03). Further meta-analyses indicated no significant SMD in the drinking quantity for all trials (SMD = −0.09, P = 0.18). Within the US trials only, a significantly lower amount of alcohol was consumed after a MI intervention (SMD = −0.12, P = 0.04). Meta-analyses based on the smallest differences in the effect size found no differences in the alcohol consumption after intervention between groups (SMD ≤ 0.02, P ≥ 0.38).
The Brazilian trial differed in several aspects from the US trials in the sample beyond its cultural setting: The experimental intervention was implemented solely by one researcher. The trial relied exclusively on self-report in evaluating the intervention effects, and with only one follow-up after 3 months it was the shortest trial in the sample. The sample was composed of ~40% of alcohol dependents in each group. This portion could be higher than in the other trials studied because brief interventions usually target risk populations at an early stage of alcohol-related problems (Segatto et al., 2011). In addition, risks associated with alcohol abuse, which may correlate with the readiness to change alcohol consumption, were not balanced at baseline and no intention-to-treat analysis was performed. Despite these differences between trials, results from the meta-analyses with and without the Brazilian trial suggested that some additional reduction in alcohol consumption can potentially be achieved by MI.
Our review and meta-analysis are subject to limitations. The methodological quality of the studies included ranges from poor to good. The major concern with respect to the quality of the meta-analyses, which were based on unadjusted raw data, is the high numbers of dropouts of at least 6.6%, and up to 30.6% of participants. These dropout rates are likely to have introduced a substantial but unexamined bias. Publication bias was indicated for the selective study of drinking frequency outcomes from US trials with the strongest MI effects. Confirming an additional impact of MI on the drinking frequency in the meta-analysis of the USA and Brazil trials, for which a possible publication bias was not indicated, mitigates our concern that estimating a positive upper bound for an additional effect of MI in emergency care brief interventions may be a result caused by publication bias. Within the original studies, few included dropouts in their final assessment (Cunningham et al., 2009) or made a sensitive analysis to investigate the worst-case situation of equating loss to follow-up with a negative answer for change attempts, at least for alcohol-related consequences (Bernstein et al., 2010).
No reviewed study states whether MI was adapted to the special needs and demands of young people as discussed, for instance, by Gillian (1991). Combined interventions, like MI plus normative resetting and skills training or MI plus 'booster' phone calls, were tested in some studies (Monti et al., 2007; Cunningham et al., 2009; Bernstein et al., 2010), preventing us from deducing the efficacy of MI on its own. The methodological differences in the analyses and interventions limit the comparability of the study findings reviewed. Finally, we did not study alcohol-related problems as an outcome. However, it is often a history of alcohol-related problems that brings a patient to the attention of a medical provider, and the reduction of these problems rather than alcohol consumption itself might be the aim of an opportunistic brief intervention.