In recent years, medical evidence has pointed to the harmful physical effects of second-hand smoke. Now, a new study adds to evidence that non-smokers who live or work around smokers can experience psychological harm as well.
Dr. Mark Hamer of University College London says previous research found that smokers have a higher rate of mental illness, specifically depression.
"The problem with that body of research is that it's difficult to interpret because obviously people with existing mental health problems use cigarettes to self-medicate," he says.
In this study, Hamer and his colleagues combined measurements of tobacco exposure with interviews focused on mental health issues. They found that nonsmokers exposed to tobacco smoke were more likely to experience psychiatric distress, and that the mental health issues increased along with the tobacco exposure.
"We found that people with high exposure to second hand smoke had increased levels of depression and anxiety," says Hamer.
They also found that people exposed to second-hand smoke - like smokers - were more likely to be admitted to a hospital for a psychiatric illness than people without the exposure to tobacco smoke.
To accurately assess the level of second-hand smoke exposure, researchers tested for cotinine, which is produced when nicotine is metabolized. But they also asked the people in the study where they were exposed to tobacco smoke. Perhaps surprisingly, says Hamer, the answer wasn't at work, restaurants, or pubs.
"The people that are at the highest level of passive smoke are actually the ones reporting exposure in their own homes. So in other words, if you live with a smoker, you really are at very high risk of demonstrating high levels of second-hand smoke exposure."
Dr. Mark Hamer's study on the psychological impact of second-hand tobacco smoke appears in the Archives of General Psychiatry, a journal published by the American Medical Association.