Passive Smoking Causes Mental Health to Decline

Over the past few years, scientists have linked numerous negative consequences to being exposed to cigarette smoke. The phenomenon, called second-hand smoking, was so widespread that many nations adopted legislation prohibiting smoking in public places, as well as in numerous bars. In a new work, experts at the University College London, in the UK, have linked exposure to tobacco smoke with psychological distress and risk of future psychiatric illness. They explain in a paper accompanying the findings that the harmful consequences of second-hand smoking (SHS) are much more extensive than previously thought, and that they go well beyond affecting just physical health.

“Animal data have suggested that tobacco may induce a negative mood, and some human studies have also identified a potential association between smoking and depression. Our data is therefore consistent with other emerging evidence to suggest a causal role of nicotine exposure in mental health. Importantly, this study advances previous research because we obtained an accurate assessment of SHS exposure using a valid biochemical indicator,” explains UCL Epidemiology & Public Health department expert Dr Mark Hamer. He is the lead author of the paper, which appears in the June 7 issue of the esteemed scientific publication Archives of General Psychiatry.

The investigation was carried out on about 5,560 non-smoking adults, as well as on 2,689 smokers without history of mental illness. “SHS exposure at home is growing in relative importance as restrictions on smoking in workplaces and public places spread. A growing body of literature has demonstrated the harmful physical effects of second hand smoke exposure, but there has been limited research about the affects on mental health,” the expert adds. The UCL researchers measured the amounts of the hormone cotinine, which can usually be associated with a person's level of exposure to cigarette smoke.

About 14.5 percent of adults in the study sample revealed symptoms of psychological distress, including those who never smoked. They also had elevated levels of cotinine in their saliva. “Mental ill health accounts for almost 20% of the burden of disease in the European Region and can affect one in four people at some time in their life. Our findings emphasize the importance of reducing SHS exposure at a population level, not only for the benefit of our physical health but for our mental health as well,” Hamer says. The new data may be used for the creation of new public policies, analysts say, which could be aimed at reducing the incidence of SHS in the general population.