Tobacco smoking is a serious public health problem. Unfortunately, smoking is a quintessential dependence disorder, evidenced by a characteristic withdrawal syndrome and heavy, uncontrolled use (1). Cardinal manifestations of uncontrolled use are both persistent use and an inability to quit successfully in a cessation attempt (1-3). Nicotine dependence is associated with both reduced likelihood of quitting over time (4) and a rapid return to smoking following a quit attempt (3, 5-7).Therefore, identification of the factors that contribute to either sustained smoking or more rapid smoking relapse should help elucidate the causal basis of tobacco dependence, permit more accurate prediction of dependence and relapse risk, and support more effective application of treatment.
