Previous research has shown that exposure to secondhand smoke increases the likelihood that children will become teenage smokers and makes it more difficult for adult smokers to quit. Such associations suggest that secondhand smoke acts on the brain to promote smoking behavior.
Christopher S. Culbertson and colleagues used positron emission tomography (PET) to demonstrate that one hour of secondhand smoke in an enclosed space results in enough nicotine reaching the brain to bind receptors that are normally targeted by direct exposure to tobacco smoke. This happens in the brain of both smokers and non-smokers.
Their study, published May 1 in Archives of General Psychiatry, shows that even limited secondhand smoke exposure delivers enough nicotine to the brain to alter its function. Chronic or severe exposure could result in even higher brain nicotine levels, which may explain why secondhand smoke exposure increases vulnerability to nicotine addiction.
The US Surgeon General's Report concluded in 2006 that secondhand smoke causes heart disease and lung cancer in nonsmoking adults and many serious health conditions in children, including sudden infant death syndrome, respiratory infections, and more severe asthma. According to the American Centers for Disease Control, almost 50,000 deaths per year can be attributed to secondhand smoke.
Journal Reference:C. S. Culbertson, J. Bramen, M. S. Cohen, E. D. London, R. E. Olmstead, J. J. Gan, M. R. Costello, S. Shulenberger, M. A. Mandelkern, A. L. Brody. Effect of Bupropion Treatment on Brain Activation Induced by Cigarette-Related Cues in Smokers. Archives of General Psychiatry, 2011;68(5):505-515.