Depression, sometimes called major depression or depressive disorder, is a mood disorder that has been called the “common cold of mental illness” because it is so common in the general population. Unlike the common cold, however, depression can have serious long-term effects on a person's quality of life.
Some types of depression are recognized as separate disorders:
- Dysthymia. Also called dysthymic disorder, dysthymia is a condition in which the person has milder symptoms of depression that are less disabling than those of major depression over a period of two years or longer.
- Psychotic depression. Patients with this type of depression have hallucinations, delusions, and other signs that they have lost contact with reality.
- Postpartum depression. This is a type of depression that affects some women following the birth of a baby.
- Seasonal affective disorder (SAD). SAD is a form of depression related to changes in the seasons. Most people with SAD feel
depressed in the winter and better in summer, but there is also a reverse form of SAD in which the person is depressed in summer and feels better in winter.
Depression is a mood disorder that does not affect everyone in the same way. There is some evidence, for example, that women and men experience depression differently; women are more likely to feel sad, worthless, or guilty, while men are more likely to feel tired, irritable, and uninterested in activities that they used to enjoy. Men appear more likely than women to get angry and act abusively toward others, or to drive recklessly. Depression in the elderly may take the form of memory problems or slowed-down movement rather than crying or feeling sad. Depression in children may have such symptoms as refusing to go to school, getting in trouble, or sulking and being generally moody and hard to get along with.
Depression also has different patterns of recurrence in different people. Some persons have one episode of depression, recover, and are never troubled by recurrences. Others have a series of episodes at irregular intervals. And as the definition of dysthymia indicates, some people have a low-grade depression that may persist for years without turning into an episode of major depression.
Depression often coexists with other mental and physical disorders, which often makes it difficult to diagnose. Depression can occur before the person gets sick; can occur as a result of the sickness; or exist alongside other illness. Mental disorders that often coexist with depression include alcoholism and substance abuse disorders, eating disorders, anxiety disorders, posttraumatic stress disorder, and obsessive-compulsive disorder. Physical disorders that commonly affect depressed patients include heart disease, stroke, cancer, AIDS, diabetes, and Parkinson disease. Depression can make the symptoms of these diseases worse and harder to treat.
Depression is one of the more common mood disorders in the United States. According to the National Institutes of Health, one in every five women and one in every eight men will have an episode of major depression at some point in their lifetime. Depression is a major cause of time lost from work, lost opportunities for education, and vulnerability to substance abuse. It is a factor in 55 percent of all suicide attempts, or about
People can suffer from depression at any age; however, adults between the ages of thirty and forty are most likely to be diagnosed with major depression. There is a second but smaller peak in adults between fifty and sixty.
- Major depression is diagnosed twice as often in women as in men; however, in children, boys are diagnosed with depression as often as girls.
- Depression appears to be less common among African Americans in the United States than among members of other racial groups.
Risk factors for depression in adult life include:
- Death of a parent during one's childhood
- A family history of depression
- A history of suicide in the family
- Long-term use of certain medications, particularly birth control pills, drugs given to treat high blood pressure, and sleeping pills
- Long-term alcohol or drug abuse
- Poverty and unemployment
- Recent bereavement or traumatic incident
The causes of depression have been debated for decades, with researchers disagreeing as to whether biology, psychology, or a combination of the two offers the best explanation. Most researchers now think that depression is the end result of biological vulnerability to a mood disorder combined with personal history and certain personality traits.
- Genetic factors. No specific genes have been identified, although the disorder is known to run in families.
- Biochemical. Researchers have found that the brains of people with depression have abnormal levels of certain brain chemicals called neurotransmitters. Neurotransmitters relay impulses from one nerve cell to the next.
- Life history. Difficult circumstances early in life, too many traumatic experiences too close together, or high stress levels over a long period of time can all make people more likely to become depressed.
- Personality factors. People who are pessimistic, easily discouraged, or inclined to worry a lot are vulnerable to depression.
An occasional blue mood or temporary feeling of discouragement is not a depression. For a diagnosis of depression a person must have five symptoms from the following list for at least two weeks. The symptoms must be severe enough to interfere with the person's daily activities and relationships:
- Depressed mood
- Loss of interest or pleasure in activities that the person used to enjoy
- Weight gain or loss
- Difficulty sleeping or sleeping much more than usual
- Slowed movement or extreme restlessness
- Lack of energy; difficulty getting things done
- Feeling worthless or hopeless
- Problems with concentrating or decision making
- Thoughts of death or suicide
The diagnosis of depression is complicated and often missed, particularly in the elderly. Diagnosis begins with a complete physical examination, partly to see whether the patient has medical problems that may increase his or her risk of depression, and partly to rule out physical reasons for changes in mood. These include thyroid disorders, infectious diseases like syphilis or Lyme disease, and prescription medications that are known to affect mood. The doctor may order blood or urine tests as part of the physical examination.
Another important part of the diagnosis is taking the patient's personal and family history. This part of the patient interview often includes giving the patient the Beck Depression Inventory or another questionnaire that can be completed in the doctor's office in a few minutes. There are special questionnaires of this sort for children and adolescents.
The doctor will also listen to the way the patient talks as well as the content of what they are saying, because depressed people often talk slowly and may sound sad. The patient's facial expressions and the way they are dressed may also provide clues; a patient who is usually neat and tidy may come to the office looking poorly groomed.
Primary care doctors will usually refer their patients to psychiatrists (mental health specialists) in order to distinguish major depression from other mental illnesses, and to prescribe treatments for the depression.
Treatment for depression may consist of antidepressant medications, psychotherapy, electroconvulsive therapy (ECT), or a combination of these approaches.
- Antidepressant medications: These are drugs that work by affecting the levels of neurotransmitters in the brain. There are several different families of antidepressant medications, and the doctor may have to try several different drugs before finding the one that works best for the patient. The choice of antidepressant also depends on whether the patient is taking prescription drugs for other health conditions. It takes anywhere from two to eight weeks for the patient to know whether the antidepressant is working for them. Between a half and two-thirds of people with depression are helped by medications.
- Psychotherapy. There are several different approaches that are used to treat depressed people. The most common ones are interpersonal therapy and cognitive therapy. In interpersonal therapy, the person learns about the causes of depression and the social triggers in his or her life that set off depressive thoughts, together with strategies for coping with their social situation. Cognitive therapy works by teaching the patient to change his or her ways of thinking. Many people have underlying negative assumptions that affect the way they see their life, and these expectations can be challenged and changed.
- Electroconvulsive therapy (ECT). Sometimes called shock therapy, ECT is a treatment in which seizures are induced in an anesthetized patient to relieve the depression. It is thought to work by changing the levels of neurotransmitters in the brain. ECT is generally used only for depressed patients who have not been helped by medications or psychotherapy.
Alternative and complementary treatments that are sometimes used for depression include various herbal remedies, such as St. John's wort. Those interested in herbal preparations should discuss these with their doctor, however, as these preparations can interact with standard prescription drugs and have side effects just like standard drugs. Other complementary therapies include acupuncture, massage therapy, music therapy, meditation, and stress reduction techniques. These are safe, and are
helpful to some patients with depression. Studies also indicate that regular exercise can be helpful in controlling symptoms of depression and anxiety.
The prognosis of depression varies considerably. People who are not treated for depression often feel better within six to twenty-four months; however, episodes of depression can be shortened considerably with treatment. About two-thirds of patients treated for depression feel well enough to return to their normal activities within a few weeks. About a quarter of patients will continue to have symptoms of depression for months to years after the first episode. About 50 percent of patients treated for depression will have a second episode at some point in time; these recurrences usually respond well to treatment, however.
People who are depressed are at increased risk of suicide. About 3.4 percent of patients diagnosed with major depression eventually succeed in committing suicide.
People cannot change some risk factors for depression, such as their family history or their sex, but they can lower their risk by taking good care of their physical health, keeping up a strong family and friendship network, learning to cope with normal life stressors, and talking to their doctor if they are concerned about their moods.
Depression is one of the oldest known mental disorders, having been described by physicians in ancient Egypt and China, and is likely to continue to be a common problem around the world. Present research includes trials of newer antidepressants, comparisons of standard treatments with various alternative therapies, and studies of the ways in which culture or ethnic background influences depression. Another important area of research is looking for ways to predict how patients will respond to specific antidepressant medications, so that the trial-and-error approach to finding the best drug for each patient could be eliminated.
SEE ALSO Bipolar disorder; Child abuse; Obsessive-compulsive disorder; Postpartum depression; Posttraumatic stress disorder; Seasonal affective disorder
WORDS TO KNOW
Delusion: In medicine, a false belief that a person holds to despite evidence or proof that it is false.
Dysthymia: A mood disorder characterized by a long-term low-key depression.
Neurotransmitters: Chemicals produced by the brain that relay nerve impulses from one nerve cell to another.
Postpartum depression: A type of depression that some women experience after the birth of a baby.
Miller. Debra A. Postpartum Depression. Detroit, MI: Lucent Books, 2008.
Willis, Laurie, ed. Depression. Detroit, MI: Greenhaven Press, 2008.
Carey, Benedict. “Lifting the Curtain on Depression.” New York Times, March 3, 2008. Available online at http://health.nytimes.com/ref/health/healthguide/esn-depression-ess.html (accessed on September 8, 2008).
Depression and Bipolar Support Alliance. Depression. Available online at http://www.dbsalliance.org/site/PageServer?pagename=about_depression_overview (updated March 12, 2007; accessed on September 8, 2008).
KidsHealth. Why Am I So Sad? Available online at http://kidshealth.org/kid/feeling/thought/sadness.html (updated November 2007; accessed on September 8, 2008).
Mental Health America (MHA). Factsheet: Depression. Available online at http://www.mentalhealthamerica.net/go/depression (updated October 31, 2007; accessed on September 8, 2008). The page contains a link to “The Down & Up Show,” a series of podcasts about depression.
National Alliance on Mental Illness (NAMI). Major Depression. Available online at http://www.nami.org/Template.cfm?Section=By_Illness&Template=/TaggedPage/TaggedPageDisplay.cfm&TPLID=54&ContentID=26414 (accessed on September 7, 2008).
National Institute of Mental Health (NIMH). What Is Depression?Available online at http://www.nimh.nih.gov/health/publications/depression/introduction.shtml (updated June 26, 2008; accessed on September 7, 2008).
Public Broadcasting Service (PBS). Depression: Out of the Shadows. Available online in video format at http://www.pbs.org/wgbh/takeonestep/depression/video-ch_01.html (accessed on September 8, 2008). This is a twelve-part series of videos based on a television program that aired on May 21, 2008. The segments range from about four minutes to nine minutes in length.