Depressive disorder (or depression) is a common and serious mental health condition defined by a lasting low mood, loss of interest in activities, and low energy that last for at least two weeks. It is not a personal weakness or a bad mood that a person can simply "snap out of".Key Signs and SymptomsSadness or emptiness: Feeling down, hopeless, or tearful most of the day.Loss of pleasure: Stopping hobbies or pulling away from friends and family.Body changes: Trouble sleeping (insomnia or sleeping too much), major appetite shifts, and extreme tiredness.Mind changes: Trouble focusing, feeling worthless, or having thoughts of self-harm and death.Common TypesMajor Depressive Disorder (MDD): Intense and ongoing sadness that disrupts daily life.Persistent Depressive Disorder: A continuous, milder low mood lasting for two years or more.Other forms: Can include seasonal patterns or changes related to medical conditions and life events.