Depression is a state of low mood that can persist for weeks or months.[1] The symptoms of depression interfere with daily life and are often present during adolescence and young adulthood but may not be diagnosed until adulthood. As of 2019, The National Center for Health Statistics reports that 4.7% of U.S. adults over 18 years of age have regular feelings of depression.
What is depression?
Written by:
Fact-checked
by:
•Last Updated: May 16, 2025
Depression is a prolonged state of low mood that can disrupt daily life; it often emerges during adolescence or young adulthood but is frequently diagnosed later on. As of 2019, 4.7% of U.S. adults over 18 experience regular feelings of depression.