The Smoke Clears on Nicotine Addiction
Written by Bupa's medical team - 19 March 2002
New research into nicotine addiction may provide vital clues for developing alternative remedies for people trying to quit smoking. Researchers from the University of Chicago in Illinois have identified the brain circuits that trigger a person's craving for cigarettes, and discovered that smokers who quit often have their first cravings as soon as an hour after their last cigarette.
Existing remedies on the market such as patches and chewing gum only partly satisfy the need for nicotine but can't replicate the rush of nicotine a smoker gets from a cigarette or the ritual of smoking. One puff on a cigarette fills the lungs with smoke sending nicotine rushing to the brain cells. This triggers a release of the 'reward' chemical dopamine, however, soon after this rush the brain cells become immune to the effects of nicotine.
The continued influx of nicotine starts to affect other brain circuits, in particular one that stops cells from releasing dopamine, raising the levels of this feel-good chemical around the body. When the brain circuit recovers and levels of dopamine drop around one hour after the cigarette, some smokers start reaching for their pack. This may explain the cycle of cravings that are associated with nicotine addiction.
Commenting on the research Daniel McGehee from the University of Chicago speculated that a chemical that stops this brain circuit rebounding could quash smoker's cravings and the subsequent reward of a smoke. "You'd disconnect smoking from the good feeling," he says.
ASH - the anti smoking pressure group - suggested that the ritual of smoking had to be tackled alongside the physical nicotine addition and emphasised that different therapies work for different people. "Most replacement therapies offer a very slow release of nicotine into the bloodstream. For some heavy smokers this may not be sufficient to satisfy their cravings." However they also see problems with quitting drugs such as Zyban that affects the brain areas involved in forming dependence: "Brain scans of heavy smokers have revealed that the cells that release dopamine have actually stopped working due to being swamped with nicotine." Implying that addiction to smoking is more to do with ritual than physical cravings.
About 13 million adults on the UK smoke cigarettes - 29 per cent of men and 25 per cent of women. Every year around 120,000 smokers in the UK die as a result of their habit.
Links:
- National Stop Smoking Advice Line: 0800 169 0169
Bupa's section on Stopping Smoking
