Commentary on Schwartz et al. (2014): Where next for face-to-face, person-to-person, computerized and online brief interventions for drug users?After decades of research on brief interventions for alcohol [1], study of applications with drug users has developed over the last 15 years or so [2], with marijuana use among adolescents and young adult students prominent in this literature. Limited specificity of intervention effects [3,4] and deterioration of short-term effects over time [5] have been features of some studies that have clear parallels with intervention research on addictive behaviours more broadly. Due to the different historical periods in which they have developed, there has been relatively early investigation of computerized and online interventions for drug users (e.g. [6,7]), including direct comparisons of automated computerized and person-toperson interventions, such as in the study by Schwartz and colleagues [8].The literature on computerized alcohol interventions has developed with important methodological shortcomings [9], with few studies being online interventions accessible on telephones and computers at the convenience of participants. This is also true of computerized interventions for drug use [10], and such is the pace of development of study that these reviews are already quite dated.There are no systematic reviews of online rather than computerized interventions, and the former may also embrace person-to-person contacts, as do telephones not connected to the internet. We need systematic reviews of face-to-face, person-to-person and automated online interventions for drug users. The distinctions made here are somewhat laboured, as too often they are overlooked. This is not trivial because it is possible, if not likely, that effectiveness in changing addictive behaviours will vary across these categories, as well as within them according to the content being employed [11]. The lack of up-todate systematic reviews is problematic, and reasonable concerns have been articulated that implementation of brief interventions for drug users is out of kilter with the development of the evidence base [12].This situation also poses difficulties for the identification of research questions, including the design of control conditions and the choice of superiority or noninferiority hypotheses. Schwarz and colleagues [8] provide a well-designed and well-conducted trial in this context. The contents of the interventions compared are similar and the absence of differences in primary outcomes unsurprising, indicating that brief face-to-face contact beyond that which is required to access the computerized intervention confers no additional benefit. The decision not to measure the fidelity of the brief face-to-face intervention is sensible in light of the effectiveness study context.The lack of concordance between the hair analysis data and the self-reported data calls for further investigation. Better understanding of the technical limitations of this validation approach is necessary in order to evaluate...