Children and teens who breathe in secondhand smoke are more likely to develop symptoms of mental health problems including major depressive disorder and attention deficit-hyperactivity disorder, a new study finds.

Health problems stemming from secondhand smoke have been well documented. These include asthma, sudden infant death syndrome (SIDS) and ear infections. But until now, the link between secondhand smoke and mental health has not been well studied. The Los Angeles Times reports this is believed to be the first study that examines how secondhand smoke exposure (as measured by a blood test for a nicotine metabolite) is associated with mental health in a nationally representative sample of children and adolescents in the United States.

The new study appears in the Archives of Pediatrics and Adolescent Medicine.