Nicotine dependence: development, mechanisms, individual differences and links to possible neurophysiological correlates.

There is now little doubt that the majority of people who smoke tobacco do so to experience the psychopharmacological properties of the nicotine present in the smoke and that a significant proportion of habitual tobacco users become addicted to the drug nicotine. In the US some 80% and in Europe (Germany) 39% of smokers have been classified as dependent according to the diagnostic guidelines of the American Psychiatric Association. As a result, direct nicotine replacement is used increasingly by many people who want to stop smoking. The objectives of this review are to outline the mechanisms involved in the development and maintenance of nicotine dependence and to link behavioural observations to possible neurophysiologic correlates.