Understanding nicotine and tobacco addiction

by Symposium on Understanding Nicotine and Tobacco Addiction (2005 Novartis Foundation)

Cigarette smoking is estimated to lead to 4.9 million premature deaths per year worldwide. This is predicted to rise to 10 million by 2020. In western countries it kills half of all smokers who fail to stop. The prevailing model for tobacco addiction is that nicotine from cigarettes rewards smoking and punishes abstinence, tapping into a motivational system of operant conditioning that requires no conscious awareness. However, there are also accounts which involve cognitive biases and the effect of nicotine on impulse control. The brain pathways involved have been studied extensively, but the role of different nicotine receptor subtypes and other neurotransmitter systems is still subject to debate. In western countries, cigarette smoking as an adult has a heritability of 30-50% and candidate genes have been identified that may contribute in part to addiction susceptibility. Many socio-cultural correlates of cigarette smoking have been established, but a comprehensive model that account