Roni Caryn Rabin
Smokers are known to suffer from high rates of depression and other mental health problems, and now a study reports that even people exposed to secondhand smoke are at significantly increased risk- and more likely to be hospitalised for mental illness.
The study analysed data from the Scottish Health Survey of 1998 and 2003, a periodic look at a nationally representative sample of about 5,560 nonsmoking adults and 2,595 smokers. The researchers used a 12-item questionnaire to assess mental health, including sleep problems and symptoms of depression and anxiety. Salivary levels of cotinine, a nicotine byproduct, were used to assess exposure to secondhand smoke.
Nonsmokers exposed to secondhand smoke were 1.5 times as likely to suffer from symptoms of psychological distress as unexposed nonsmokers, the study found, and the risk increases the greater their exposure to passive smoking.
And though psychiatric hospitalisations were rare over all, the exposed nonsmokers were also almost three times as likely to have to be admitted to a psychiatric hospital, according to the study, published online this month (June 7) in Archives of General Psychiatry.
While the association between smoking and mental health problems has long been known, researchers have never been able to establish whether people with mental illness are more likely to pick up the cigarette habit, or whether smoking may actually help cause mental illness, said the paper’s lead author, Mark Hamer, a senior research fellow at University College London.
“This research goes some way toward suggesting nicotine is having some sort of impact on mental health,” Dr. Hamer said. “But of course, we need to do further work