Secondhand smoke exposure and mental health among children and adolescents.

OBJECTIVE To examine a potential association between biologically confirmed secondhand smoke exposure and symptoms of Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) (DSM-IV) major depressive disorder, generalized anxiety disorder, panic disorder, attention-deficit/hyperactivity disorder, and conduct disorder using a nationally representative sample of US children and adolescents. DESIGN Nationally representative cross-sectional survey of the United States. SETTING Continental United States. PARTICIPANTS Children and adolescents aged 8 to 15 years who participated in the National Health and Nutrition Examination Survey from 2001 to 2004. INTERVENTION Measurement of serum cotinine level to assess secondhand smoke exposure among nonsmokers. MAIN OUTCOME MEASURES The DSM-IV symptoms were derived from selected modules of the National Institute of Mental Health's Diagnostic Interview Schedule for Children Version IV, a structured diagnostic interview administered by trained lay interviewers. RESULTS Among nonsmokers, serum cotinine level was positively associated with symptoms of DSM-IV major depressive disorder, generalized anxiety disorder, attention-deficit/hyperactivity disorder, and conduct disorder after adjusting for survey design, age, sex, race/ethnicity, poverty, migraine, asthma, hay fever, maternal smoking during pregnancy, and allostatic load. Associations with serum cotinine level were more apparent for boys and for participants of non-Hispanic white race/ethnicity. CONCLUSIONS Our results are consistent with a growing body of research documenting an association between secondhand smoke exposure and mental health outcomes. Future research is warranted to establish the biological or psychological mechanisms of association.