Smoking is a habit that can lead to a host of health problems. Besides increasing the risk of lung cancer and dental problems, smoking can also cause problems for those who live with the smoker. Research is increasingly highlighting the health problems that are caused by the exposure to secondhand smoke. A recent study examined how secondhand smoke affects children. Often, children at risk of exposure to secondhand smoke are the least able of any family member to control the environment around them. When parents or other adults living in the house use cigarettes, kids are forced to live with the health risks that accompany secondhand smoke. The study was conducted by the University College London to determine how the mental health of kids was affected by exposure to secondhand smoke. The study recruited a sample of 901 children to measure the impact of secondhand smoke on mental health. The researchers found that there was a connection between the amount of secondhand smoke a child was exposed to and the condition of their mental health. For instance, the researchers found that particularly among children diagnosed for hyperactivity or exhibiting "bad" behavior, there was a high level of exposure to secondhand smoke. In order to understand the connections between mental health and secondhand smoke, the researchers conducted a number of exercises. The level of secondhand smoke exposure was gauged using a saliva test for each child. The parents of the child participants were asked to fill out a questionnaire that gathered information about mental wellness. The parents were asked to report about social, behavioral and emotional aspects of the child's mental health. The researchers found that the results were consistent even when certain variables were accounted for. For instance, the researchers controlled for factors such as family income, housing or asthma. Each of these variables are factors that may also contribute to overall mental health. The findings of the study add to a growing body of research confirming the adverse effects of secondhand smoke, particularly for those most vulnerable to environmental exposures. Small children do not have the ability to control their surroundings, and if their parents choose to smoke, they are powerless to avoid exposure. The results may provide information helpful in developing educational materials suitable for encouraging parents to consider eliminating smoke from the home. Findings are published in Archives of Pediatrics and Adolescent Medicine.