It's not known exactly what causes depression. A variety of factors may be involved. These include:

  • Biological chemistry. Neurotransmitters are naturally occurring brain chemicals that likely play a role in depression. When these chemicals are out of balance, it may lead to depression symptoms.
  • Hormones. Changes in the body's balance of hormones may be involved in causing or triggering depression.
  • Inherited traits. Depression is more common in people whose biological (blood) relatives also have the condition.
  • Early childhood trauma. Traumatic events during childhood, such as physical or emotional abuse, or loss of a parent, may cause changes in the brain that make a person more susceptible to depression.
  • Learned patterns of negative thinking. Teen depression may be linked to learning to feel helpless — rather than learning to feel capable of finding solutions for life's challenges.
Nov. 07, 2012