Consistent with previous estimates from the National Comorbidity Survey (Wagner and Anthony, 2002a), the cumulative probability of transition from use to dependence a decade after use onset was 14.8% among cocaine users, 11.0% among alcohol users, and 5.9% among cannabis users. This probability was 15.6% among nicotine users. Furthermore, lifetime cumulative probability estimates indicated that 67.5% of nicotine users, 22.7% of alcohol users, 20.9% of cocaine users, and 8.9% of cannabis users would become dependent at some time in their life. Pharmacokinetic, environmental and physiological factors may contribute to explain the higher rates of transition from nicotine use to dependence compared to transition from use to dependence of other substances. For instance, the rate of absorption in the extensive surface area of alveoli attained from smoking nicotine (Henningfield and Keenan, 1993; Samaha and Robinson, 2005) is far greater than the rate of absorption of alcohol or cocaine in the nasal and gastro-intestinal mucosae (Fattinger et al., 2000; Norberg et al., 2003). The higher social acceptability of nicotine use compared to other substances also increases the exposure to environmental, situational and
