ability to explain the differences between groups. Another limitation is that the cannabis use item on the NESARC assessed “joints and joint equivalents” but did not directly assess other methods of cannabis use. Because the NESARC did not assess the mixing of tobacco with cannabis, it is possible that some participants within the CUD only group could have some degree of nicotine dependence and be unaware of this. Potential areas of future research are an analysis of how psychiatric diagnoses mediate the association of co-occurring cannabis use disorders and nicotine dependence with treatment outcomes; an analysis of how alcohol and non-cannabis substance use disorders moderate the association of co-occurring cannabis use disorders and nicotine dependence with the correlates investigated herein; inclusion of individuals who engage in the increasingly popular practice of simultaneous use of cannabis and tobacco (i.e., “blunt” smoking, “chasing;” Akre et al., 2010; Barrett et al., 2006; Golub et al., 2005; Kelly, 2005; Soldz et al., 2003); a longitudinal analysis of whether co-occurring cannabis and tobacco use precedes psychiatric and psychosocial problems or vice versa; and replication of findings among individuals who meet DSM-5 (APA, 2013) criteria for cannabis and tobacco use disorders.
