The effects of secondhand smoke on the lungs and on the heart have been clearly demonstrated in previous studies.  Now it appears that secondhand smoke might also affect one's mental health.

A new study examined more than 5000 non-smoking adults and more than 2500 smoking adults.  Each participant, none of whom had a history of mental illness, was asked about psychological distress and admission to psychiatric hospitals.  The participants were followed for a period of six years.

Researchers found that non-smokers who were exposed to a significant amount of secondhand smoke were 50 percent more likely to suffer from psychological distress than those who were not exposed to secondhand smoke.  The risk of non-smokers exposed to secondhand smoke being admitted to a psychiatric hospital within the next six years nearly tripled.

Overall, more than 14 percent of the participants reported psychological distress.  The greater the exposure to secondhand smoke, the greater the risk of distress, which was highest among those who were smokers.  Non-smokers who were exposed to high levels of secondhand smoke were 62 percent more likely to suffer from psychological distress than those who were not exposed.  The risk of hospitalization for mental illness was more than twice as great for non-smokers exposed to secondhand smoke.  The effects were stronger for those who had never smoked before than for those who had quit smoking.

These results suggest that there may be a link between tobacco and depression.  Secondhand smoke exposure is typically measured by the amount of cotinine, a nicotine byproduct, that is found in the body's system.  However, there are limited studies examining how secondhand smoke can affect mental health.  Thus, the findings of this new study offer additional insights into the link between secondhand smoke and mental health while calling for more research into this emerging area of study.