Depression or depress may refer to:

[ Psychology

• Depression (mood), a lack of positive affect
• Colloquially, Adjustment disorder with depressed mood, previously known as Reactive depression.
• Major depressive disorder a clinical diagnosis of a state of intense sadness
  • Melancholic depression a sub-type of clinical depression characterized by an inability to feel pleasure combined with physical agitation, insomnia, or decreased appetite
  • Atypical depression, a cyclical sub-type of clinical depression where sleep, feeding and perception of pleasure are normal but there is a feeling of lethargy
  • Psychotic depression, a sub-type of clinical depression combined with psychotic or delusional perceptions
  • Postnatal depression, clinical depression following childbirth
• Depression is the 4th stage of the Kübler-Ross model (commonly known as the "stages of dying").

[ Physiology

• Depression (physiology), a reduction in a biological variable or the function of an organ
• Depression (kinesiology), an anatomical term of motion

[ Other

• Depression (geology), a sunken landform
• In economics, a depression is an economic downturn more severe than a recession
  • The Great Depression was a severe economic depression in the 1930s
• In meteorology, a depression is an area of low atmospheric pressure
• "Depress", a song by Eyehategod from the album In the Name of Suffering
• "Depression", a song by Black Flag from the album Damaged