Exposure to secondhand smoke, such as a person can get by riding in an enclosed car while someone else smokes, has a direct, measurable impact on the brain — and the effect is similar to what happens in the brain of the person doing the smoking. In fact, exposure to this secondhand smoke evokes cravings among smokers, according to a study funded by the National Institute on Drug Abuse (NIDA), part of the National Institutes of Health.

The study, published in the journal Archives of General Psychiatry, 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 [1]. This happens in the brain of both smokers and non-smokers.

The brains of infants who die of sudden infant death syndrome (SIDS) produce low levels of serotonin, a brain chemical that conveys messages between cells and plays a vital role in regulating breathing, heart rate, and sleep, reported researchers funded by the National Institutes of Health.

SIDS is the death of an infant before his or her first birthday that cannot be explained after a complete autopsy, an investigation of the scene and circumstances of the death, and a review of the medical history of the infant and of his or her family. According to the National Center for Health Statistics, SIDS is the third leading cause of infant death, claiming more than 2,300 lives in 2006.