Young people with asthma have nearly twice the incidence of depression compared to their peers without asthma, and studies have shown that depression is associated with increased asthma symptoms and, in some cases, death.
How stress and depression play upon one another to worsen asthma is a lingering question.
A new study by researchers at the University at Buffalo has shown that depressed children with asthma exhibit a dysregulation of the autonomic nervous system along with increased airway compromise.
It is thought to be the first study to examine pathways linking emotional stress, depressive symptoms, autonomic nervous system dysregulation and airway function in childhood asthma.
The study appears in the July 2009 issue of the Journal of Allergy and Clinical Immunology.
Bruce D. Miller, M.D., and Beatrice L. Wood, Ph.D., professors of psychiatry and pediatrics in the UB School of Medicine and Biomedical Sciences, designed and carried out the study in collaboration with other UB researchers.
"The autonomic nervous system, or ANS, is composed of two opposing divisions -- the sympathetic and parasympathetic nerves, which check one another and thus control critical body functions outside of conscious awareness," explained Miller, chief of the UB Division of Child & Adolescent Psychiatry and senior staff psychiatrist at Women & Children's Hospital of Buffalo, a UB-affiliated teaching hospital. "The ANS is influenced by stress and emotions."
"Children with asthma and high depression symptoms showed a preponderance of parasympathetic over sympathetic nervous system reactivity in the ANS," he continued. "This imbalance within the ANS could explain the increased airway resistance that we found in depressed asthmatic children in our study."
The study involved 90 children with asthma, aged 7-17. Forty-five asthmatic children with symptoms of depression were compared with 45 asthmatic children without symptoms of depression. Both groups viewed scary, sad (death) and happy scenes from the movie E.T.: The Extraterrestrial.
All children wore electrodes to collect data on heart and respiratory function, which showed the level of activation and reactivity of the sympathetic and parasympathetic divisions. The researchers assessed airway function before the movie, after the death scene and after the movie.