What causes depression?

There are many theories about what causes depression. Depression may be caused by any of these things:

  • changes in brain chemicals
  • heredity
  • negative thinking patterns
  • major stresses
  • certain illnesses
  • certain medications
  • lack of sunlight
  • hormonal changes
  • job strain

There is no single cause of depression. Healthcare providers don't know exactly what causes most depression. Some depression starts in response to a difficult event such as the death of a loved one. Other times, depression seems to come on for no obvious reason. Several factors might work together to bring on your depression. Often the cause is just not known.