2009; Gray et al., 2011; Haney et al., 2012; Moore and Budney, 2001) and may have a negative impact on tobacco treatment outcomes (Abrantes et al., 2009; Ford et al., 2002; Gourlay et al., 1994; Haskins et al., 2010; Hendricks et al., 2012; Metrik et al., 2011; Patton et al., 2005; Stapleton et al., 2009). Tobacco may substitute for reduced cannabis consumption, potentially creating further substance-related problems (Allsop et al., 2012).
