What is Major Depression?

Major depression is a serious medical illness affecting 9.9 million American adults, or approximately 5 percent of the adult population in a given year. Unlike normal emotional experiences of sadness, loss, or passing mood states, major depression is persistent and can significantly interfere with an individual's thoughts, behavior, mood, activity, and physical health. Major depression is the leading cause of disability in the U.S. and many other developed countries.

Nearly twice as many women (6.7 million) as men (3.2 million) suffer from major depressive disorder each year. Major depression can occur at any age including childhood, the teenage years and adulthood. All ethnic, racial and socioeconomic groups suffer from depression. More than half of those who experience a first episode of depression will have at least one other episode in their lives. Some individuals may have several episodes in the course of a year. If untreated, episodes commonly last anywhere from six months to a year. Left untreated, depression can lead to suicide.

Major depression, also known as clinical depression or unipolar depression, is only one type of depressive disorder. Other depressive disorders include dysthymia (chronic less severe depression) and bipolar disorder (manic depression). People who have bipolar disorder experience both depression and mania. Mania involves abnormally and persistently elevated mood or irritability, elevated self-esteem, and excessive energy, thoughts, and talking.

What are the symptoms of major depression?

The onset of the first episode of major depression may not be obvious if it is gradual or mild. The symptoms of major depression characteristically represent a significant change from how a person functioned before the illness. The symptoms of depression include:

When several symptoms of depression occur, last longer than two weeks, and interfere with ordinary functioning professional treatment is needed.

What are the causes of major depression?

There is no one single cause of major depression. Psychological, biological, and environmental factors may all contribute to its development. Whatever the specific causes of depression, scientific research has firmly established that major depression is a biological brain disorder.

Norepinephrine, serotonin, and dopamine are three neurotransmitters (chemical messengers that transmit electrical signals between brain cells) thought to be involved with major depression. Scientists believe that if there is a chemical imbalance in these neurotransmitters, then clinical states of depression result. Antidepressant medications work by increasing the availability of neurotransmitters or by changing the sensitivity of the receptors for these chemical messengers.

Scientists have also found evidence of a genetic predisposition to major depression. There is an increased risk for developing depression when there is a family history of the illness. Not everyone with a genetic predisposition develops depression, but some people probably have a biological make-up that leaves them particularly vulnerable to developing depression. Life events, such as the death of a loved one, a major loss or change, chronic stress, and alcohol and drug abuse, may trigger episodes of depression. Some illnesses and some medications may also trigger depressive episodes. It is also important to note that many depressive episodes occur spontaneously and are not triggered by a life crisis, physical illness, or other risks.

How is major depression treated?

Although major depression can be a devastating illness, it is highly treatable. Between 80 and 90 percent of those suffering from serious depression can be effectively treated and return to their normal daily activities and feelings. Many types of treatment are available, and the type chosen depends on the individual and the severity and patterns of his or her illness. There are three basic types of treatment for depression: medications, psychotherapy, and electroconvulsive therapy (ECT). They may be used singly or in combination.

What are the side effects of the medications used to treat depression?

All medications have side effects. Different medications produce different side effects, and people differ in the amount and severity of side effects they experience. About 50 percent of people who take antidepressant medications have some side effects during the first weeks of treatment, but these problems are usually temporary and mild. Side effects that are particularly bothersome can often be treated by changing the dose of the medication, switching to a different medication, or treating the side effect directly with an additional medication.

Reviewed by Rex Cowdry, M.D. NAMI medical director, May 2001