Major depressive disorder (MDD) (also known as clinical depression, major depression, unipolar depression, unipolar disorder or recurrent depression in the case of repeated episodes) is a mental disorder characterized by episodes of all-encompassing low mood accompanied by low self-esteem and loss of interest or pleasure in normally enjoyable activities. Major depressive disorder is a disabling condition that adversely affects a person’s family, work or school life, sleeping and eating habits, and general health.

Causes

The exact cause of depression is not known. Many researchers believe it is caused by chemical changes in the brain. This may be due to a problem with your genes, or triggered by certain stressful events. More likely, it’s a combination of both.
Some types of depression run in families. But depression can also occur if you have no family history of the illness. Anyone can develop depression, even kids.

The following may play a role in depression:

• Alcohol or drug abuse?
• Certain medical conditions, including underactive thyroid, cancer, or long-term pain
• Certain medications such as steroids
• Sleeping problems
• Stressful life events, such as:
• Breaking up with a boyfriend or girlfriend
• Failing a class
• Death or illness of someone close to you
• Divorce
• Childhood abuse or neglect
• Job loss
• Social isolation (common in the elderly)

See also: Adolescent depression

Symptoms

Depression can change or distort the way you see yourself, your life, and those around you.
People who have depression usually see everything with a more negative attitude. They cannot imagine that any problem or situation can be solved in a positive way.

Symptoms of depression can include:

• Agitation, restlessness, and irritability
• Becoming withdrawn or isolated
• Difficulty concentrating
• Dramatic change in appetite, often with weight gain or loss
• Fatigue and lack of energy
• Feelings of hopelessness and helplessness
• Feelings of worthlessness, self-hate, and guilt
• Loss of interest or pleasure in activities that were once enjoyed
• Thoughts of death or suicide
• Trouble sleeping or too much sleeping

Depression can appear as anger and discouragement, rather than feelings of sadness.

If depression is very severe, there may also be psychotic symptoms, such as hallucinations and delusions.

Treatment

In general, treatments for depression include:

• Medications called antidepressants
• Talk therapy, called psychotherapy

If you have mild depression, you may only need one of these treatments. People with more severe depression usually need a combination of both treatments. It takes time to feel better, but there are usually day-to-day improvements.