Four groups were defined according to different levels of substance dependence: control (CTR), drinker (DRN), smoker (SMK), and smoking and drinking (SAD). The DRN group is composed of 28 subjects that scored 8 or greater on the Alcohol Use Disorder Identification Test (AUDIT) (Saunders et al., 1993). The maximum Fagerstrom Test for Nicotine Dependence (FTND) score for the DRN group is 4. The SMK group includes 73 smokers with a FTND score greater than 7 (Fagerstrom et al., 1990). The SAD group consists of 36 subjects that scored greater than 8 on the AUDIT and greater than 7 on the FTND. There is no significant difference in AUDIT score between SAD and DRN groups and there is no significant difference of FTND score between SAD and SMK groups. Detailed information about the four groups can be found in Table 1. The threshold used to select subjects for the DRN have been used before to detect hazardous drinking (Vergara et al., 2016; Weiland et al., 2014) and corresponds to the minimum criteria for at-risk drinking (Babor et al., 2001). The SMK
