Reviewing and interpreting the effects of brief alcohol interventions: comment on a Cochrane review about motivational interviewing for young adults [For debate] (2016)

Background: Cochrane recently published a systematic review on motivational interviewing (MI) for alcohol misuse in young adults. The review authors concluded that 'there are no substantive, meaningful benefits of MI interventions for the prevention of alcohol misuse' (p. 2), as effect sizes were 'small and unlikely to be of any meaningful benefit in practice’ (p. 27). As most of these interventions were quite brief, we wish to open a dialogue about interpreting effect sizes in this review and of (brief) alcohol interventions more generally.
Analysis: We analyze four methodological aspects of the review that likely influenced the author's conclusions about intervention effects: (1) risk of bias assessments, (2) search strategies, (3) assessing the quality of the body of evidence and (4) definitions of sustainability and clinical significance.
Conclusions: We interpret the effect sizes found in this review to indicate modest yet beneficial and potentially meaningful effects of these interventions, given their brevity and low cost. This interpretation is consistent with other reviews on brief, MI-based interventions and brief interventions more generally. We therefore encourage the field to re-open dialogue about the clinical importance of the effects of MI on alcohol misuse by young adults. Rather than dismissing interventions with small effects, we believe a more fruitful way forward for the field would be to catalogue effect sizes for various alcohol interventions. Such a catalogue would help stakeholders themselves to choose which interventions meet their minimum desired impact, and thus may be suitable given their targeted populations, setting and resources.