Exposure to secondhand smoke has similar effects on the brain of both smokers and nonsmokers, according to research funded by the National Institute on Drug Abuse (Brody AL et al. Arch Gen Psychiatry. doi: 10.1001/archgenpsychiatry.2011.51 [published online ahead of print May 2, 2011]).
The study of 11 moderately dependent cigarette smokers and 13 nonsmokers found 1 hour of secondhand smoke in an enclosed space resulted in nicotine reaching the brain, in smokers and nonsmokers alike, to bind nicotinic acetylcholine receptors that are normally targeted by direct exposure to tobacco smoke. Secondhand smoke also evoked cravings among the smokers, suggesting that it may deliver a priming dose of nicotine to the brain that contributes to continued cigarette use in smokers.
Hampton T. Effects of Secondhand Smoke. JAMA. 2011;305(24):2510. doi:10.1001/jama.2011.868