Depression | Causes & Risk Factors


What causes depression?

Depression may be caused by an imbalance of chemicals in the brain. Sometimes there aren't enough chemical messengers (called neurotransmitters) in the brain. Examples of neurotransmitters that affect your mood are serotonin (say: "sair-a-tone-in"), norepinephrine (say: "nor-ep-in-ef-rin"), and dopamine (say: “dope-a-mean”). A chemical imbalance in the brain may be caused by one or more of the following:

  • Your genes. Sometimes depression is hereditary, meaning it runs in your family. If you have a parent or sibling who has depression, you may be more at risk for having depression yourself.
  • A medical condition. Problems with your thyroid, nutrient deficiencies, or chronic diseases such as heart disease, diabetes, or cancer may cause depression.
  • Events in your life. Depression can be triggered by stressful events in your life, such as the death of someone you love, a divorce, chronic illness, or loss of a job.
  • Medicines, drugs, or alcohol. Taking certain medicines, abusing drugs or alcohol, or having other illnesses can also lead to depression.

Depression is not caused by personal weakness, laziness, or lack of willpower.

Can giving birth cause depression?

In the days following the birth of a baby, it is common for some mothers to have mood swings. They may feel a little depressed, have a hard time concentrating, lose their appetite, or find that they can't sleep well even when the baby is asleep. This is called the baby blues and goes away within 10 days after delivery. However, some women have worse symptoms or symptoms that last longer. This is called postpartum depression.


See a list of resources used in the development of this information.

Written by editorial staff

Reviewed/Updated: 08/12
Created: 06/96