Major depressive disorder (MDD)—also known as unipolar depression or simply major depression—is a serious clinical mood disorder in which feelings of sadness, frustration, loss, or anger interfere with a person's everyday life for weeks or months at a time.

People with MDD are more likely to use alcohol or illegal substances than others, are at increased risk for other mental and physical health problems, and are at a much greater risk for suicide than the general population.


The exact cause of major depressive disorder is not known, however many researchers believe it is linked to chemical changes in the brain, problems with a person's genes, or a combination of both. It tends to run in families, but can also occur in those with no family history of the disease.

Alcohol and drug abuse may play a role in MDD, as can other medical conditions such as an under-active thyroid and certain types of cancer. Other conditions associated with the disease include sleep problems as well as some types of medications, including steroids.

Major depressive disorder can also be triggered by stressful events in a person's life. These may include:

  • job loss
  • divorce or separation
  • failing a class
  • death or illness of a friend or family member
  • physical or emotional abuse
  • social isolation


People with major depressive disorder tend to have a distorted view of their lives in which a negative attitude makes it difficult for them to imagine how problems or situations may be resolved in a positive way. Other symptoms may include:

  • irritability
  • difficulty with concentration
  • fatigue or lack of energy
  • feelings of hopelessness and/or helplessness
  • feelings of worthlessness, guilt, or self-hate
  • social isolation
  • loss of interest in once pleasurable activities
  • sleep problems (insomnia or excessive sleeping)
  • dramatic changes in appetite along with corresponding weight loss or gain
  • suicidal ideation or behavior

In more severe cases of MDD, patients may experience psychotic symptoms such as delusions or hallucinations.

Diagnosing Major Depressive Disorder

A physician or other health care provider will typically ask a patient about his symptoms and medical history. Questionnaires are usually used to aid a doctor with diagnosis and help determine the severity of the depression. In addition, blood or urine tests may be administered in order to rule out other possible medical conditions.

Treatments for Major Depressive Disorder

Treatments for major depressive disorder usually include medications, talk therapy, or both. For most people with more serious forms of clinical depression such as MDD, antidepressants are the first line of attack.

Common types of antidepressants include selective serotonin reuptake inhibitors (SSRIs) such as citalopram (Celexa), fluoxetine (Prozac), escitalopram (Lexapro) and sertraline (Zoloft).

Other types of medication include older-style tricyclic antidepressants (which may not be well-tolerated by older patients), a serotonin norepinephrine reuptake inhibitor (SNRI) such as venlafaxine (Effexor), or bupropion (Wellbutrin).

Talk therapies help a person develop coping skills to deal with her depression. They include cognitive behavioral therapy, which teaches a person how to deal with negative thoughts and develop problem-solving skills. Psychotherapy is used to help a person understand issues behind negative thoughts and feelings. Support groups are another way to help people deal with their MDD. Talk therapy tends to work better in combination with other therapies such as antidepressants.

Alternative therapies such as St. John's Wort and acupuncture may help relieve symptoms of more mild forms of depression, but studies reveal they may be ineffective for more serious types of depression, including MDD. A person should consult with a physician before relying on an alternative treatment as—especially in the case of St. John's Wort—they may have potentially dangerous interactions with certain types of medications.

Regular exercise has been found to be effective treatment for most types of depression and can be ?performed safely in conjunction with other therapies. It has the added benefit of helping to improve a person's physical as well as mental health.

Electroconvulsive therapy (ECT) has proven to be a very effective (and safe) treatment for those with the most severe cases of MDD, those who haven't responded well to other treatments and in those who experience psychotic symptoms.

Prognosis for Those with MDD

Typically it takes people several weeks to feel better after beginning a regimen of antidepressants. The average length of time for an episode of MDD is usually nine months, however many people will require ongoing treatment depending on the severity of their illness and 80 to 90 percent of patients will remit within two years.

A person experiencing thoughts of suicide or of harming others should immediately contact an emergency number such as 911, call the suicide hotline at 1-800-SUICIDE (1-800-784-2433, 24 hours a day, 7 days a week), or get to a hospital emergency room.