Depression can cause the following phenomena: 1. Depressed patients mainly show low mood, negative thoughts, sullenness, reduced interest, reluctance to meet people, always like to shut a person in the house, do not want to do something or slightly do something to feel overwhelmed, energy decline. 2. Low self-esteem, negative thoughts, a sense of worthlessness, a sense of uselessness, a lack of pleasure in everything you do, a lack of pleasure, sometimes sleep disorders, and in severe cases, thoughts or behaviors of self-harm and self-abandonment.