Psychological factors such as anxiety and depression are prevalent in patients with asthma. The purpose of this study was to investigate the relationship between respiratory symptoms and psychological status and to estimate the importance of psychological status in comparison with other factors that are known to be associated with respiratory symptoms.

This study included 2270 subjects aged 20–44 (52% female) from Sweden, Iceland, and Norway. Each participant underwent a clinical interview including questions on respiratory symptoms. Spirometry and methacholine challenge were performed. Symptoms of depression and anxiety were measured using the Hospital Anxiety and Depression Scale (HADS).

Eighty-two percent of the subjects reported no anxiety or depression whatsoever, 11% reported anxiety, 2.5% depression and 4% reported both anxiety and depression. All respiratory symptoms, such as wheezing, breathlessness and nightly symptoms, were more common, at a statistically significant level, in participants who had depression and anxiety, even after adjusting for confounders (ORs 1.33 – 1.94). The HADS score was the most important determinant for nightly symptoms and attacks of breathlessness when at rest whereas bronchial responsiveness was the most important determinant for wheezing, and breathlessness when wheezing. The probability of respiratory symptoms related to HADS score increased with increasing HADS score for all respiratory symptoms.

In conclusion, there is a strong association between respiratory symptoms and psychological status. There is therefore a need for interventional studies designed to improve depression and anxiety in patients with respiratory symptoms.