The clinical manifestations of depression include core symptoms primarily characterized by low mood, reduced interest, and lack of emotion. Patients often display an inability to feel joy, experiencing a persistent sadness and a noticeable decrease in interest and pleasure in activities they previously enjoyed. The psychological symptoms are dominated by anxiety, slowed thinking, and cognitive symptoms, with patients exhibiting irritability, tension, worry, and often slow thought association, dull thinking, impaired short-term memory, reduced attention, and significantly diminished learning, comprehension, and judgment abilities. The physical symptoms include sleep disturbances, eating disorders, and loss of energy, with common issues like difficulty falling asleep, light sleep, early waking, poor appetite, weight loss, feeling listless, fatigue, and an overwhelming sense of exhaustion in their daily lives.