This observational study aims to estimate the prevalence and severity of depression among patients with coronary artery disease (CAD) in Baghdad, Iraq, using the self-administered PHQ-9 questionnaire. The study seeks to answer the following questions: What is the prevalence of depression among CAD patients? How is the severity of depression distributed within this group? Are specific demographic, clinical, or environmental factors associated with higher levels of depression? Participants will: Complete the PHQ-9 to assess the severity of depressive symptoms at a specific point in time. Provide demographic and clinical information, including age, gender, socioeconomic status, comorbidities, and CAD-related factors such as type of intervention and duration of illness, to explore potential correlations with depression.