Background: Anxiety and depression are psychological conditions that are highly prevalent among patients with chronic lung disease. These conditions are associated with increased morbidity and, in certain groups, increased mortality. Cognitive behaviour therapy (CBT) has shown potential as a treatment of anxiety and depression among patients with COPD, asthma and bronchiectasis. Pulmonary rehabilitation has the strongest evidence regarding its benefit in these patients, mainly through improved physical capacity and education. Consequently, the combination of both treatments (CBT and pulmonary rehabilitation) is promising, with potentially enhanced therapeutic benefits. The primary aim of this thesis was to determine the impact of cognitive behavioural therapy (CBT) as a treatment for patients with chronic lung disease and psychological comorbidities undergoing pulmonary rehabilitation. The study also assessed risk factors for the presence of anxiety and depression in patients attending pulmonary rehabilitation, the effect of CBT on quality of life and, through a subgroup analysis, the impact of mild cognitive impairment on CBT.Methods: A parallel group, randomised controlled trial (RCT) was conducted, with longitudinal follow-up of 12 months. Participants were screened from the pulmonary rehabilitation program at The Prince Charles Hospital and recruited if they had Geriatric Depression Scale (GDS) ≥4/15 or Geriatric Anxiety Inventory (GAI) ≥3/20, suggestive of depression or anxiety, respectively. In addition to pulmonary rehabilitation, the Intervention group received CBT comprised by two face-to-face sessions and 4 phone sessions, while the Control group received usual care. The main outcome measures were GDS and GAI; secondary outcomes were St. Georges Respiratory Questionnaire (SGRQ), pulmonary rehabilitation attendance and 6 minute walk test (6MWT).
Results:The majority of patients attending pulmonary rehabilitation had COPD (58.5%), with the remainder having asthma (19.7%), interstitial lung disease (ILD) (9%) and bronchiectasis (12.4%). Of the patients screened, 25 (13%) had only symptoms of anxiety, 33 (17%) of only depression and 62 (32%) had symptoms of both anxiety and depression. Anxiety and depression were strongly correlated with SGRQ (p<0.01) and pulmonary rehabilitation program attendance. GDS scores were also correlated with 6MWT (p<0.01), past smoking (p<0.01), body-mass index (p<0.01), and body-mass index, airflow obstruction, dyspnea, and exercise capacity index (BODE) scores (p<0.01); while GAI was not correlated with other parameters. 65 patients were randomised to the study (24 in the Intervention group, 41 in the Control group). Of the 24 patients in the Intervention group, 10 (42%) failed to attend pulmonary rehabilitation or withdrew from the study. In the Intervention group, GDS significantly improved, compared to baseline, at the end of rehabilitation (mean difference -3.1, 95% CI -4.39 to -1.7; P<0.01), 3 months follow-up (mean difference -1.46, 95% CI -4.17 to -0.75; P<0.01) and 12 m...