This "Clinical Guide" is an effort to develop a practical, operational model of an educational and regulatory document for physicians—primarily those working in primary health care (PHC). Currently, Ukraine lacks methodological guidelines for providing psychiatric care within general medical practice. The guide offers an overview of the importance of mental health issues, explores concepts of affective disorders, and covers epidemiology, etiology, and classification of depressive conditions. It also addresses ethical and legal considerations in delivering medical and psychiatric care. Additionally, the book provides practical instructions on conducting psychiatric interviews, recognizing, diagnosing, and treating depressive disorders.