cannabis use disorder. All PSU met DSM-IV dependence criteria for at least one illicit substance and 10.5% met criteria for cannabis use disorder. Specifically, 12 PSU met criteria for cocaine dependence (63%) and 2 of these were either abusing or dependent on cannabis; 2 other PSU met criteria for both cocaine and methamphetamine dependence (10.5%); and yet 2 others were dependent on both cocaine and opiates (10.5%); 2 other PSU met criteria for methamphetamine dependence only (10.5%) and 1 for opiate dependence only (5.5%). In the PSU group, 32% were non-smokers, including 2 ex-smokers. All ALC participants met DSM-IV criteria for alcohol dependence with or without nicotine dependence. 15ALC participants (37%) were non-smokers, including 6 ex-smokers; the proportion of smokers did not differ among ALC and PSU. All ex-smokers among ALC and PSU individuals had stopped smoking for at least 5 years before the study. Within the ALC group, 2 individuals were currently abusing cannabis, while 3 had past cannabis abuse, currently in full remission. In addition, one ALC participant each showed past dependence on cocaine, amphetamines, or opioids, but all were currently in full remission. Thus, while the ALC participants were “clean” alcohol dependent individuals, the PSU participants were
