major depressive disorder

Depression is a type of mental disorder with complex pathological causes, characterized primarily by low mood as its main symptom. Patients with major depressive disorder may exhibit pessimism, world-weariness, despair, hallucinations, delusions, loss of appetite, functional decline, and may be accompanied by severe suicidal ideation or even suicidal behavior. It poses a serious threat to human health and therefore must be given high priority and treated promptly. Mood disorders: patients experience poor mood, emotional dejection, or anxiety, irritability, and restlessness; loss of interest in daily activities, loss of pleasure, frowning and worrying all day long; reduced energy, often feeling persistent fatigue; believing that life is meaningless, and in severe cases feeling hopeless and helpless, wishing they were dead, feeling that days pass like years, with most patients having thoughts of ending their own lives.