As evidence on the significance of co-occurring use of cannabis and tobacco accumulates, several critical gaps in the literature have yet to be addressed. Although some studies have found differences in symptoms of anxiety and negative affect in individuals who use both cannabis and tobacco relative to individuals who use cannabis or tobacco only (Bonn-Miller et al., 2010; Georgiades and Boyle, 2007; Moore and Budney, 2001; Suris et al., 2007), no studies have examined the prevalence of psychiatric disorders among individuals who use both. This is surprising, given that identifying psychiatric disorders among individuals with co-occurring cannabis and tobacco use is an important first step for their treatment as well as for indicating how future interventions for this population need to be tailored to also address psychiatric disorders.
