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Depression - Introduction

Description

An in-depth report on the causes, diagnosis, treatment, and prevention of depression.

Alternative Names

Seasonal affective disorder

Introduction:

Everyone experiences some unhappiness, often as a result of a change, either in the form of a setback or a loss, or simply, as Freud said, "everyday misery." The painful feelings that accompany these events are usually appropriate, necessary, and transitory, and can even present an opportunity for personal growth. However, when depression persists and impairs daily life, it may be an indication of a depressive disorder. Severity, duration, and the presence of other symptoms are the factors that distinguish normal sadness from a depressive disorder.

Depression has been alluded to by a variety of names in both medical and popular literature for thousands of years. Early English texts refer to "melancholia," which was for centuries the generic term for all emotional disorders.

Depression is now referred to as a mood disorder, and the primary subtypes are major depression, dysthymia (chronic and usually milder depression), and atypical depression. Other important forms of depression are premenstrual dysphoric disorder (PDD or PMDD) and seasonal affective disorder (SAD).

Depression is defined as a mood disorder, and there are several subtypes. Bipolar disorder, also known as manic-depressive illness, is considered in a separate category.

The other major mood disorder is bipolar disorder, formerly called manic-depressive illness, which is characterized by periods of depression alternating with episodes of excessive energy and activity. Bipolar disorder is not discussed in this report. [For more information, see In-Depth Report #66: Bipolar disorder.]

Major Depression

In major, or acute, depression, at least five of the symptoms listed below must occur for a period of at least 2 weeks, and they must represent a change from previous behavior or mood. Depressed mood or loss of interest must be present. Symptoms include:

1. Depressed mood on most days for most of each day -- irritability may be prominent in children and adolescents
2. Total or very noticeable loss of pleasure most of the time
3. Significant increases or decreases in appetite, weight, or both
4. Sleep disorders, either insomnia or excessive sleepiness, nearly every day
5. Feelings of agitation or a sense of intense slowness
6. Loss of energy and a daily sense of tiredness
7. Sense of guilt or worthlessness nearly all the time
8. Inability to concentrate occurring nearly every day
9. Recurrent thoughts of death or suicide

In addition, other criteria must be met:

The symptoms listed above do not follow or accompany manic episodes (such as in bipolar disorder or other disorders).
They impair important normal functions (such as work or personal relationships).
They are not caused by drugs, alcohol, or other substances.
They are not caused by normal grief.

A long-term study found that episodes of major depression usually last about 20 weeks.

Dysthymia (Chronic Depression)

Dysthymia, or chronic depression, afflicts 3 - 6% of the general population and is characterized by many of the same symptoms that occur in major depression. Symptoms of dysthymia are less intense and last much longer, at least 2 years. The symptoms of dysthymia have been described as a "veil of sadness" that covers most activities. Possibly because of the duration of the symptoms, patients who suffer from chronic minor depression do not exhibit marked changes in mood or in daily functioning, although they have low energy, a general negativity, and a sense of dissatisfaction and hopelessness.

Double Depression. Often, symptoms become more severe over time. In one long-term study, nearly all patients with dysthymia suffered at least one episode of major depression superimposed over chronic depression (sometimes called double depression) at some time in their life. Some doctors believe that such double depression should be considered as part of the natural course of dysthymic disorder.

Atypical Depression

About a third of patients with depression have atypical depression. Symptoms include overeating and oversleeping. Such patients tend to have a feeling of being weighed down and react strongly to rejection. Atypical depression tends to occur more in women, unmarried people, and those with other emotional disorders, such as anxiety or substance abuse. It may also impair functioning more severely than ordinary depression.

Seasonal Affective Disorder

Seasonal affective disorder (SAD) is characterized by annual episodes of depression during fall or winter that improve in the spring or summer. Other SAD symptoms include fatigue and a tendency to overeat (particularly carbohydrates) and oversleep in winter. A minority of individuals with SAD have the more common depressive symptoms of undereating and being sleepless. SAD tends to last about 5 months in those who live in the northern part of the U.S.

Seasonal changes affect many people's moods, regardless of gender and whether or not they have SAD. Simply being mildly depressed during the winter does not mean that one has SAD. Living in a northern country with long winter nights does not guarantee a higher risk for depression. Changes in light may not be the only contributor to SAD.

Resources

www.nimh.nih.gov -- National Institute of Mental Health
www.dbsalliance.org -- Depression and Bipolar Support Association
www.fda.gov/cder/drug/antidepressants -- FDA Antidepressant Use in Children, Adolescents, and Adults
www.parentsmedguide.org -- American Psychiatric Association-sponsored information on pediatric antidepressants
www.nami.org -- National Alliance on Mental Illness
www.nmha.org -- Mental Health America
www.aabt.org -- Association for Behavioral and Cognitive Therapies
www.psych.org -- American Psychiatric Association
www.apa.org -- American Psychological Association
www.aacap.org -- American Academy of Child and Adolescent Psychiatry
www.postpartum.net -- Postpartum Support International
www.mentalhealth.samhsa.gov -- National Mental Health Information Center
www.mentalhealth.samhsa.gov/suicideprevention/concerned.asp -- National Strategy for Suicide Prevention (if contemplating suicide, call 1-800-273-TALK)
www.suicidology.org -- American Association of Suicidology

References

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Reviewed last on: 1/22/2009
Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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