“…In the included studies, 'drug use' is approached in different ways. Multiplicity in the usage of terms can be observed in the methods section: 'drug use' (Bakken et al, 2014;Colman and Vander Laenen, 2012;O'Connell et al, 2007;Taylor, 2008;Wooditch et al, 2014), 'drug use problems' (Landale and Roderick, 2014), 'dependent use' (Tiburcio, 2008), 'drug abuse' (Davis, 2012;Ronel et al, 2013;Taylor, 2008), 'drug dependence' (Ronel et al, 2013), 'drug abuse problems' (Bahr et al, 2012;Griffin and Armstrong, 2003), 'substance misuse' (Walters, 1996), 'drug involvement' (Martin et al, 2011) and 'drug addiction' (Marsh, 2011;McCray et al, 2011). The majority of the included articles (n = 11) do not specify a particular drug type or types for inclusion in the study, so that it is possible that the sample includes users of a diverse range of substances.…”