Tobacco can influence both stress and anxiety levels and can be mood altering, according to the latest research on tobacco addiction presented during the conference.
Dr Jon Kassel of the University of Illinois, Chicago, reported on his findings that nicotine narrows the field of attention of the brain, so that the smoker does not react as much as the non-smoker to external distractions. In research just completed, he found the greatest reduction in anxiety levels among smokers who consumed high-yield nicotine cigarettes. This backs up previous research which confirms that regular smokers experience reduced stress levels.
Dr Carol Paronis of Harvard Medical School in Boston described research which showed that stress increases a smoker's nicotine consumption. She described animal experiments which suggested that nicotine did indeed reduce anxiety levels.
Nicotine inhaled in smoke passes quickly through the bloodstream and into the brain, resulting in an intense "hit" which reinforces the smoking behaviour. Nicotine is known to provide a stimulus which enhances satisfaction, affects performance and controls mood and body weight.
There is compelling evidence to show that smokers use the nicotine from tobacco as a mood regulator. Many former smokers experience depression during withdrawal.
These findings make the approval of the new smoking cessation drug, bupropion, even more interesting. An established antidepressant, it is the first non-nicotine medication shown to be effective for smoking cessation.
Researchers from the Mayo Clinic in Rochester, Minnesota, presented a paper showing that the long-term use of bupropion prevents smoking relapse and results in less weight gain following cessation.
Bupropion is available in the Republic on prescription for use with nicotine replacement therapy. The new drug is contra-indicated in people with a history of seizures, eating disorders and for anyone already taking some antidepressant medication. Dr Kathleen Merikangas of Yale University School of Medicine presented a study called "The genetic epidemiology of Smoking". One of her main findings is that of a "maternal effect". If a child's mother smokes, the child is more likely to be a heavy regular nicotine user than if the father smokes.
Delegates also heard that smoking is much more common in alcoholics. Dr Andrew Heath told the conference there may be significant overlap between the genetic influences of becoming a regular smoker and those which influence the risk of alcohol dependence.
In his plenary address, the director of the US National Institute on Drug Abuse, Mr Alan Leshner, exhorted the audience to take the scientific facts of nicotine addiction and use them to educate the public. "People start smoking because they like what it does to their brain," he said. "Nicotine rewires the brain."