Symptoms of depression impact the course of lung function in adolescents and adults with cystic fibrosis

BACKGROUND: Epidemiological studies report high rates of depression among patients with cystic fibrosis (CF). Assuming a causal relationship between depression and the progression of CF, our hypothesis is that elevated symptoms of depression would be a predictor of worse lung function after two years. METHODS: In the context of the TIDES study, 473 German patients with CF (age 12–53 years, FEV(1)% predicted M = 66.2, range 13–137) completed the Hospital Anxiety and Depression Scale (HADS). Lung function (FEV(1)% predicted) was assessed at baseline and followed up two years later. Repeated measures analysis was performed involving the level of FEV(1)% and the level of depressive symptoms at baseline as independent factors and FEV(1)% at the 2-year follow-up as the dependent variable. RESULTS: Interaction between lung function and depression at baseline significantly affected the change in lung function at the 2-years observation interval. The largest decline in FEV(1)% occurred in depressed patients with good lung function at baseline. In contrast, patients without any clinically relevant depressive symptoms and with poor lung function at baseline showed a slight increase two years later. CONCLUSION: The findings emphasise the need to screen patients with CF for symptoms of depression and to treat co-morbid depression.