Depression (also known as major depression, major depressive disorder, or clincal depression) is a common but serious mood disorder. It causes severe symptoms that how a person feels, thinks, and handles daily activities, such as sleeping, eating, or working.
Link to article: https://www.nimh.nih.gov/health/topics/depression#:~:text=Depression%20(also%20known%20as%20major,sleeping%2C%20eating%2C%20or%20working.