Can depression have a direct effect on pulmonary functioning?
The influence of emotional states on pulmonary function in asthma has been studied extensively [40]. Recent findings indicate that airways are reactive to psychological states, with these reactions causing changes consistent with greater airway instability and asthma exacerbations [41]. Consistent with this finding, personal retrospective accounts of asthma exacerbations have also suggested that changes in emotional states often result in asthma exacerbations [42]. In the laboratory, Ritz et al [43] found increased total respiratory resistance in subjects with asthma (but not those without asthma) following exposure to depressing stimuli. Krommydas et al [44] reported that individuals with asthma and symptoms of depression (measured by the Personal Disturbance Scale (DSSI/sAD)) had significantly lower FEV1% than individuals with asthma who showed no symptoms of depression. It is not clear from this study, however, whether the results are due to the depression or the depression is due t
