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Beware the Illusory Relaxation of Cigarettes
> 10/2/2007 12:52:12 PM

There are a lot of beliefs about what tempts youths to try smoking�rebellion, thrill-seeking, advertising, emotional problems, etc.� and many studies have supported the idea that one or more of these factors contribute to the decision to try the first cigarette, but researchers at the University of Massachusetts Medical School may have found the primary reason why that first cigarette turns into the second and then the thousandth. Dr. Joseph DiFranza just finished a four-year study, covered in this month�s issue of the Journal of Pediatrics, that he set up to answer the question of why some kids who try smoking can look back bemusedly at their experimentation and others remain hooked for life.

Dr. DiFranza�s team conducted interviews with 1246 sixth-graders, asking about their first smoking experience and collecting a variety of information on personality, environment, and behavior. Because so many factors are suspected of influencing the risk of smoking, the researchers started with a wide list of 45 possible predictors. Most of these� factors turned out to have no predictive power for future nicotine dependence. Novelty-seeking personality and familiarity with tobacco advertising (represented in this study by recognition of the mascot Joe Camel) had a correlation with some of the ICD-10 measures, but not to the full definition of dependence. Depression did have a significant correlation with dependence, but this is old news. The interesting part of DiFranza�s study is that a heretofore overlooked factor, a feeling of relaxation with the first use of a cigarette, had the strongest correlation to dependence out of all other 45 factors. Only 29% of subjects were relaxed by their first cigarette, but of those who were relaxed, 91% lost autonomy and 67% eventually met all the criteria for dependence.

This interview-gleaned evidence is perfectly complimented by an unaffiliated but concurrent discovery made by the Scripps Research Institute (SRI) in the laboratory. Researchers at the SRI noticed that rats displayed anxiety during withdrawal and scanned their brains to find out exactly what was going on. They found that the extrahypothalamic corticotropin releasing factor (CRF) system was particularly excited for at least two months after the last intake of nicotine. They suspect that this part of the amygdala is altered by nicotine so that it produces excessive anxiety when nicotine is absent. The long period of CRF hyperactivity could be the reason that human smokers find it so hard to get rid of cravings. If this is true, then nicotine addicts may soon get some good news. The SRI administered CRF receptor antagonist to rats and found that the injection both reduced the symptoms of withdrawal and the doses of nicotine that rats chose each day. A similar injection might free those who want to quit from the anxiety of withdrawal, leaving only habit and the craving for pleasure to overcome.

The CRF system may very well be the reason why some smokers become dependent. It is possible that some of the children interviewed by DiFranza had CRF systems particularly vulnerable to nicotine alteration, or particularly capable of producing strong anxiety in general. Prodded by persistent anxiety, smoking can turn from a seemingly fun way to relax into the only way to reduce unbearable tension.

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