Chronic Obstructive Pulmonary Disease and Depression-The Vicious Mental Cycle.

Background: Chronic obstructive pulmonary disease (COPD) is a heterogeneous lung condition marked by persistent airflow limitation and is currently the fourth leading cause of death worldwide, accounting for 3.5 million deaths in 2021. While its physical manifestations such as dyspnea, chronic cough, and sputum production are well known, its psychological impact, particularly the high prevalence of depression among patients, remains under-recognized. Objectives: This narrative review aims to summarize the existing data on the association between COPD and depression, analyze their pathophysiological connections, explore treatment possibilities, and highlight the interrelationships between these conditions. Methods: A non-systematic literature search was conducted using PubMed, Scopus, and Google Scholar. Studies, reviews, and key publications addressing the relationship between COPD and depression were selected based on clinical relevance. Findings were synthesized thematically to provide a comprehensive and critical overview. Results: Depression in patients with COPD is linked to worse quality of life, increased functional impairment, higher suicide risk, and poorer adherence to treatment. Contributing mechanisms include chronic systemic inflammation, hypoxemia, oxidative stress, and psychosocial risk factors such as low educational level, socioeconomic disadvantage, and comorbidities. Despite evidence of this strong association, treatment strategies remain limited and underutilized, and no unified approach has yet been established. Conclusions: Depression represents a major comorbidity in COPD that exacerbates both disease burden and patient suffering. Further research is essential to clarify the underlying mechanisms and to develop integrated therapeutic approaches. Enhancing our understanding and management of this comorbidity holds promise for significantly improving patient outcomes and overall quality of life.