On the other hand, although the plausible mechanism by which the ACE‐I/D polymorphism contributes to the severity of nicotine dependence may also differ in MS when compared to depression (Baghai et al., 2008), whether it differs in comparison to a healthy population is disputable because reports disagree about its influence on the number of cigarettes smoked per week and/or pack‐year smoking history among healthy subjects (Baghai et al., 2008; Hubacek et al., 2004). Here, ACE is linked to nicotine dependence.