A perceptive observation found that those who suffer a stroke with damage to the insula found it easy to quit smoking and prompted a recent Report (1) in the journal Science. The authors suggest that treatments that “modulate the function of the insula will be useful in helping smokers quit.”
However, the analysis should set off alarm bells. Those with normal insula function find it difficult to quit smoking. Those who suffer stroke with damage to the insula find it easy to quit. In fact, if subject N is representative of the class with a damaged insula, he did not just forget to smoke. After years of pleasurable smoking activity, his dreams of smoking were now described as disgusting. He became so disgusted by the smell, he asked for another room. Showing no interest in activities that the person used to find pleasurable is a sign of depression. The cessation process produces former smokers with an increased risk for depressive symptoms (2) similar to subject N. The stroke process transformed him into a classic “anti-smoker.”
Many insular stroke victims have altered feelings related to disgust (3), empathy (4), punishment, and social shunning (5). They are often confabulatory and deny their illness (6). This is consistent with efforts by the tobacco control program to denormalize smoking (7): exaggerating the harmful effects of tobacco use and environmental tobacco smoke; using pejorative terms such as addiction and stupid and filthy habit; and encouraging ostracization and exorbitant taxes (8). The more salient finding of this study suggests that in this select population, a strong negative feeling against smoking may have a pathological basis and is a risk factor for a lesioned insula.
Certainly, further research is needed. If these findings extend to the rest of the population, it could be an important indicator of an unrecognized and often denied silent stroke. However, an investigation would have to be suspect if it is heavily influenced by those with any strong feelings about tobacco use.
Jay R. Schrand
Independent Researcher
References and Notes
1. N. H. Naqvi, D. Rudrauf, H. Damasio, A. Bechara, Science 315, 531 (2007).
2. A. H. Glassman, L. S. Covey, F. Stetner, S. Rivelli, Lancet 357, 1929 (2001).
3. A. J. Calder, J. Keane, F. Manes, N. Antoun, A. W. Young, Nat. Neurosci. 3, 1077 (2000).
4. L. Carr, M. Iacoboni, M. C. Dubeau, J. C. Mazziotta, G. L. Lenzi, Proc. Natl. Acad. Sci. 100, 5497 (2003).
5. S. Blakeslee, New York Times, 6 February 2007, p. F6.
6. A. Carota, F. Staub, J. Bogousslavsky, Curr. Opin. Neurol. 15, 57 (2002).
7. R. Bayer, J. Stuber, Am. J. Public Health. 96, 47 (2006).
8. J. R. Schrand, Am. J. Public Health 94, 1475 (2004).
9. In 1994, the author requested an educational grant from the Council for Tobacco Research to study the relationship between tobacco use and sleep apnea. This request was denied. However the letter seems to have become part of the tobacco archives: http://tobaccodocuments.org/ctr/60024574 4574.html. Aside from this, the author has no financial interest in the tobacco, diet, or health industries other than as a consumer of their products and services.
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