Literature Collection

Patients treated for drug addiction have high asthma and COPD prevalence rates. The relative contributions of cigarette smoking, smoking intensity and possible smoking of other substances has not been described. We aimed to describe the prevalence and determinants of asthma and COPD in patients prescribed methadone as opioid substitution therapy (OST). In a cross-sectional study of an anonymised patient-level primary care dataset of UK inner-city general practices (n = 46), 321,395 patients aged ≥18 years were identified. A total of 676 (0.21%) had a record of a methadone ever issued in primary care. The association between respiratory disease and methadone prescribing was examined using logistic regression. Models were adjusted for potential effects of clustering by practice. A total of 97.3% of patients prescribed methadone were cigarette smokers, either current (81.2%) or ex-smokers (16.1%). The prevalences of asthma and COPD were higher in methadone patients (14.2% and 12.4%, respectively) compared to non-methadone patients (4.4% and 1.1%, respectively). Methadone was an independent determinant of asthma, adjusting for smoking status (OR 3.21; 95% CI: 2.52, 4.10) or for smoking intensity (3.08; 2.27, 4.19), and of COPD, adjusting for smoking status (6.00; 4.61, 7.80) or for smoking intensity (5.80; 4.12, 8.17). COPD and asthma prevalence were substantially higher in those prescribed methadone compared to those never prescribed methadone. Prescription of methadone was an independent predictor for both COPD and asthma, even after adjustment for smoking status and smoking intensity. Possible explanations include confounding by association with smoking of heroin or crack cocaine, both of which may have a causal association with COPD and asthma.

Anxiety and depression are common comorbidities in patients with chronic obstructive pulmonary disease (COPD), which can contribute to increased morbidity, reduced quality of life, and worse clinical outcomes. Nevertheless, these psychological conditions remain largely overlooked. This narrative review includes studies published between 1983 and 2025 to synthesise the current evidence on the risk factors, clinical impacts, and therapeutic strategies for these comorbidities. While the exact mechanisms leading to their increased prevalence are not fully understood, growing evidence implicates a combination of biological (e.g., systemic inflammation), social (e.g., isolation and stigma), and behavioural (e.g., smoking and inactivity) factors. Despite current guidelines recommending the identification and management of these comorbidities in COPD, they are not currently included in COPD assessments. Undetected and unmanaged anxiety and depression have serious consequences, including poor self-management, non-adherence to medications, increased risk of exacerbation and hospitalisations, and even mortality; thus, there is a need to incorporate screening as part of COPD assessments. There is robust evidence showing that pulmonary rehabilitation, a core non-pharmacological intervention, can improve mood symptoms, enhance functional capacity, and foster psychosocial resilience. Psychological therapies such as cognitive behavioural therapy (CBT), mindfulness-based approaches, and supportive counselling have also demonstrated value in reducing emotional distress and improving coping mechanisms. Pharmacological therapies, particularly selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs), are commonly prescribed in moderate to severe cases or when non-pharmacological approaches prove inadequate. However, the evidence for their efficacy in COPD populations is mixed, with concerns about adverse respiratory outcomes and high discontinuation rates due to side effects. There are also barriers to optimal care, including underdiagnosis, a lack of screening protocols, limited provider training, stigma, and fragmented multidisciplinary coordination. A multidisciplinary, biopsychosocial approach is essential to ensure early identification, integrated care, and improved outcomes for patients with COPD.