Breathing in secondhand tobacco smoke may have mental health consequences for a child, as well as physical ones, British researchers reveal in the journal Archives of Pediatrics and Adolescent Medicine. The authors say they found an association between secondhand smoke and more psychological distress among children. There has been growing evidence over the last few years that parents and guardians should make every effort to make sure children are not exposed to environmental tobacco smoke.

Secondhand smoke (smoking), also known as passive smoking or environmental tobacco smoke is inhaled involuntarily or passively by an individual who is not smoking.

The authors explain that children who are regularly inhaling environmental tobacco smoke have a higher risk of developing hyperactivity, “conduct disorder” (bad behavior), and some other mental health problems.

Mark Hamer, PhD, from University College London and team gathered data on the physical and mental health of 901 children aged 4 to 8 years from a community-based population sample from the 2003 Scottish Health Survey.; all of them non-smokers. Their saliva was tested for cotinine, a by-podruct of tobacco smoke, in order to gauge their levels of secondhand smoke exposure. They were also asked to report on how frequently they were exposed to environmental tobacco smoke.

The children’s parents were asked to complete a Strengths and Difficulties Questionnaire in order to assess psychological distress, i.e. the questionnaire helped the researchers determine what emotional, behavioral, and/or social problems the children might have. The questionnaire had a top score of 40 – the higher the score the more problems the child had.

The investigators found that the presence and severity of mental health problems was closely linked to whether a child breathed in secondhand smoke, as well as how regularly. The two main problems were hyperactivity and conduct disorder.

3% of all the children had a score of at least 20 in the questionnaire. The average score of the 361 children who breathed in the most tobacco smoke was 44% higher than the 101 kids who breathed in the least.

When environmental smoke was breathed in, it was most likely to occur in the child’s home.

Even after making adjustments for factors which could have an impact on the results, such as physical activity, asthma, single-parent status, BMI (body mass index), and socioeconomic levels, the difference was still there.

Nobody knows what the link between secondhand smoke and mental problems may be due to, the authors added. Genetics may play a factor, or perhaps chemicals in tobacco smoke may influence brain chemicals, such as dopamine.

Further, larger and longer-lasting studies are required to confirm these findings, as well as determining why the association is there.

The authors concluded:

    “Objectively assessed SHS (secondhand smoke) exposure was associated with poorer mental health among children.”

“Objectively Measured Secondhand Smoke Exposure and Mental Health in Children – Evidence From the Scottish Health Survey”
Mark Hamer, PhD; Tamsin Ford, PhD; Emmanuel Stamatakis, PhD; Samantha Dockray, PhD; G. David Batty, PhD
Arch Pediatr Adolesc Med. Published online December 6, 2010. doi:10.1001/archpediatrics.2010.243

Written by Christian Nordqvist