Exposure to Secondhand Smoke Affects Brain Function

Many people believe that secondhand smoke isn’t actually harmful to nonsmokers; however, new research shows that being exposed to secondhand smoke in an enclosed space for just one hour affects the brain in the same way as direct nicotine exposure does, even in non-smokers.

Almost 50,000 deaths per year can be attributed to secondhand smoke, according to the Centers for Disease Control and Prevention. In 2006, the Surgeon General’s Report stated that secondhand smoke can cause heart disease and lung cancer in nonsmoking adults and several health conditions in children, including sudden infant death syndrome (SIDS), respiratory infections, and severe asthma.

The current study, published May 1 in the Archives of General Psychiatry, demonstrated through positron emission tomography (PET) that one hour of exposure to secondhand smoke in an enclosed space (such as a car) results in enough nicotine reaching the brain to bind to receptors that are normally targeted by direct tobacco smoke. This occurs in the brains of both smokers and non-smokers.

Previous research has suggested that exposure to secondhand smoke in childhood increases the likelihood of becoming a smoker in adolescence, and that secondhand smoke exposure makes it more difficult for smokers to quit. These findings suggest that secondhand smoke promotes smoking behavior in the brain.

Nora Volkow, MD, director of the National Institute on Drug Addiction (NIDA), said that these studies show that even limited exposure to secondhand smoke provides enough nicotine to alter the brain’s function. Chronic or extreme exposure could result in even higher amounts of nicotine reaching the brain, which could explain why secondhand smoke increases an individual’s vulnerability to nicotine addiction.

Corresponding author of the study Arthur Brody, MD, of the UCLA Department of Psychiatry and Biobehavioral Sciences, added that these findings provide evidence to support policies that ban smoking in public places, especially those that are enclosed and could expose children to secondhand smoke.

Source: Science Daily, Secondhand Smoke May Increase Vulnerability to Nicotine Addiction, May 2, 2011