In addition to increased withdrawal symptoms, faster metabolizers described themselves as more highly addicted compared with the slower metabolizers. We failed to find any significant correlation between the metabolic ratio and more traditional measures of addiction such as the mFTQ. When we removed the frequency of cigarettes smoked per day from the questionnaire, the mFTQ was still not correlated with the metabolic ratio (p=.26). Similar to our present findings, no association between the Fagerström Test for Nicotine Dependence (FTND) and the metabolic ratio were found in samples of adult smokers (13, 25, 26). Our findings that more rapid metabolizers report higher levels of addiction is consistent with other reports indicating that genetically slow metabolizers (based on the presence of CYP2A6 gene variants known to be associated with poor metabolism) are less highly dependent on average than are smokers with genetically normal metabolism (8).
