Cause

Depression is a disease. It is not caused by personal weakness and is not a character flaw. When you have depression, chemicals in your brain called neurotransmitters are out of balance.

Most experts believe a combination of family history (your genes) and stressful life events may cause depression.

• Genes: Your chance of having a bout of depression is greater if other family members have had depression. You may have inherited a trait that makes you more likely to get depressed. If this is true for you, a stressful life event is more likely to trigger depression.
• Life events: Stressful life events can trigger depression. For example, you could become depressed if you have:
  • Lost a loved one.
  • Had a baby (depression after childbirth).
  • Recently divorced.
  • Been diagnosed with a long-term (chronic) disease such as diabetes or heart disease.

Sometimes even happy life events, such as a marriage or promotion, can trigger depression because of the stress that comes with change.

Just because you have a family member with depression or have stressful life events doesn't mean you'll get depression. You also may get depression without going through a stressful event.

Other causes

Health problems also can cause depression. For example, both anemia and an underactive thyroid gland (hypothyroidism) can lead to depression. Treating the health problem usually cures the depression.

Certain medicines, such as steroids or narcotics, can cause depression. If you stop using the medicine, the depression may go away.