Respiratory symptoms and mental disorders among youth: results from a prospective, longitudinal study

To determine the relationship between respiratory symptoms and mental disorders among youth in the community, and to investigate possible mechanisms of these linkages.

Data were drawn from the Oregon Adolescent Depression Project (n = 1,709), a longitudinal study of adolescents in the community. Multiple logistic regression analyses were used to examine the cross-sectional and longitudinal associations between respiratory symptoms and mental disorders at baseline, and linkages between respiratory symptoms at baseline and the onset of specific mental disorders at follow-up. Additional analyses were performed to examine the strength and specificity of the relationship between respiratory symptoms and mental disorders. The potential roles of hypochondriasis, functional impairment, and cigarette smoking in the associations between respiratory symptoms and mental disorders were investigated.

Respiratory symptoms were associated with a significantly increased odds of any mental disorder (odds ratio (OR) = 1.9), specifically any depressive disorder (OR = 1.9), major depression (OR = 1.9), any substance use disorders (OR = 1.6), panic attacks (OR = 3.1), and attention deficit/hyperactivity disorder (ADHD) (OR = 5.8) at baseline. Respiratory symptoms at between 1987 and 1989 (Time 1) were associated with significantly increased risk of the onset of any mental disorder a year later (Time 2) (OR = 2.1). While demographic differences, hypochondriasis, functional impairment, and cigarette smoking contributed to the relationships between respiratory symptoms and mental disorders, these associations persisted after adjusting for these factors.

The results suggest evidence of an association between respiratory symptoms and mental disorders among youth in the community. While demographic differences, hypochondriasis, functional impairment, and cigarette smoking may contribute to the linkage, these factors do not appear to completely explain the association. Future studies that can replicate these findings and include an examination of other possible mechanisms for these patterns of comorbidity, such as shared familial vulnerability or other environmental risk factors (e.g., childhood behavioral risk factors), are needed next.