Depression, clinically referred to as depressive disorder, is a type of mood disorder. Its primary manifestations are persistent and significant low mood, reduced volition, and slow thinking. It is accompanied by sleep disturbances, eating disorders, low self-esteem, difficulty concentrating, feelings of guilt and self-blame. Patients do not feel pleasure or interest, sometimes feel excessively guilty, and even find life meaningless, leading to thoughts and behaviors of suicide. In severe cases, depression may also present with psychotic symptoms such as hallucinations and delusions. If these symptoms occur daily, are present most of the time, and persist for more than two weeks, significantly affecting work, study, daily life, social interactions, and family functions, then it can be diagnosed as depression. This describes the relevant clinical aspects of depression.