What is "depression"

Depression \De*pres"sion\, n. [L. depressio: cf. F. d['e]pression.]

1. The act of depressing.

2. The state of being depressed; a sinking.

3. A falling in of the surface; a sinking below its true place; a cavity or hollow; as, roughness consists in little protuberances and depressions.

4. Humiliation; abasement, as of pride.

5. Dejection; despondency; lowness.

   In a great depression of spirit.
   --Baker.

6. Diminution, as of trade, etc.; inactivity; dullness.

7. (Astron.) The angular distance of a celestial object below the horizon.

8. (Math.) The operation of reducing to a lower degree; -- said of equations.

9. (Surg.) A method of operating for cataract; couching. See Couch, v. t., 8.

   Angle of depression (Geod.), one which a descending line makes with a horizontal plane.

   Depression of the dewpoint (Meteor.), the number of degrees that the dew-point is lower than the actual temperature of the atmosphere.

   Depression of the pole, its apparent sinking, as the spectator goes toward the equator.

   Depression of the visible horizon. (Astron.) Same as Dip of the horizon, under Dip.

   Syn: Abasement; reduction; sinking; fall; humiliation; dejection; melancholy.

late 14c. as a term in astronomy, from Old French depression (14c.) or directly from Latin depressionem (nominative depressio), noun of action from past participle stem of deprimere "to press down, depress" (see depress).\n

\nAttested from 1650s in the literal sense; meaning "dejection, depression of spirits" is from early 15c. (as a clinical term in psychology, from 1905); meteorological sense is from 1881 (in reference to barometric pressure); meaning "a lowering or reduction in economic activity" was in use by 1826; given a specific application (with capital D-) by 1934 to the one that began worldwide in 1929. For "melancholy, depression" an Old English word was grevoushede.

n. 1 (lb en geography) An area that is lower in topography than its surroundings. 2 (lb en psychology) In psychotherapy and psychiatry, a state of mind producing serious, long-term lowering of enjoyment of life or inability to visualize a happy future. 3 (lb en psychology) In psychotherapy and psychiatry, a period of unhappiness or low morale which lasts longer than several weeks and may include ideation of self-inflicted injury or suicide. 4 (lb en meteorology) An area of lowered air pressure that generally brings moist weather, sometimes promoting hurricanes and tornadoes. 5 (lb en economics) A period of major economic contraction. 6 (lb en economics US) Four consecutive quarters of negative, real GDP growth. See NBER. 7 (lb en biology physiology) A lowering, in particular a reduction in a particular biological variable or the function of an organ, in contrast to elevation.

1. n. a mental state characterized by a pessimistic sense of inadequacy and a despondent lack of activity [ant: elation]

2. a long-term economic state characterized by unemployment and low prices and low levels of trade and investment [syn: slump, economic crisis]

3. a sunken or depressed geological formation [syn: natural depression] [ant: natural elevation]

4. sad feelings of gloom and inadequacy

5. a time period during the 1930s when there was a worldwide economic depression and mass unemployment [syn: the Depression, the Great Depression]

6. an air mass of lower pressure; often brings precipitation; "a low moved in over night bringing sleet and snow" [syn: low, low pressure]

7. a state of depression and anhedonia so severe as to require clinical intervention [syn: depressive disorder, clinical depression]

8. a concavity in a surface produced by pressing; "he left the impression of his fingers in the soft mud" [syn: impression, imprint]

9. angular distance below the horizon (especially of a celestial object)

10. pushing down; "depression of the space bar on the typewriter"

In economics, a depression is a sustained, long-term downturn in economic activity in one or more economies. It is a more severe downturn than an economic recession, which is a slowdown in economic activity over the course of a normal business cycle.

A depression is an unusual and extreme form of recession. Depressions are characterized by their length, by abnormally large increases in unemployment, falls in the availability of credit (often due to some form of banking or financial crisis), shrinking output as buyers dry up and suppliers cut back on production and investment, large number of bankruptcies including sovereign debt defaults, significantly reduced amounts of trade and commerce (especially international trade), as well as highly volatile relative currency value fluctuations (often due to currency devaluations). Price deflation, financial crises and bank failures are also common elements of a depression that do not normally occur during a recession.

Depression or depress(ed) may refer to:

Depression in physiology and medicine refers to a lowering, in particular a reduction in a particular biological variable or the function of an organ. It is in contrast to elevation.

For example, it is possible to refer to "depressed thyroid function" or to a depression of blood flow in a particular area.

Further examples:

• Depression of the central nervous system of an animal may be expressed as drowsiness or sleep, lack of coordination and unconsciousness.

Depression is a state of low mood and aversion to activity that can affect a person's thoughts, behavior, feelings and sense of well-being.

People with a depressed mood can feel sad, anxious, empty, hopeless, helpless, worthless, guilty, irritable, angry, ashamed or restless. They may lose interest in activities that were once pleasurable, experience loss of appetite or overeating, have problems concentrating, remembering details or making decisions, experience relationship difficulties and may contemplate, attempt or commit suicide. Insomnia, excessive sleeping, fatigue, aches, pains, digestive problems or reduced energy may also be present.

Depressed mood is a feature of some psychiatric syndromes such as major depressive disorder, but it may also be a normal reaction, as long as it does not persist long term, to life events such as bereavement, a symptom of some bodily ailments or a side effect of some drugs and medical treatments.

A depression in geology is a landform sunken or depressed below the surrounding area. Depressions may be formed by various mechanisms.

Erosion-related:

• Blowout: a depression created by wind erosion typically in either a partially vegetated sand dune ecosystem or dry soils (such as a post-glacial loess environment).
• Glacial valley: a depression carved by erosion by a glacier.
• River valley: a depression carved by fluvial erosion by a river.
• Area of subsidence caused by the collapse of an underlying structure such as sinkholes in karst terrain.
• Sink: an endorheic depression generally containing a persistent or intermittent (seasonal) lake, a salt flat (playa) or dry lake, or an ephemeral lake.

Collapse-related:

• Sinkhole: a depression formed as result of the collapse of rocks lying above a hollow. This is common in karst region.
• Kettle: a shallow, sediment-filled body of water formed by melting glacial remnants in terminal moraine.
• Thermokarst hollow: caused by volume loss of the ground as the result of permafrost thawing.

Impact-related:

• Impact crater: a depression created by an impact such as a meteorite crater.

Sedimentary-related:

• Sedimentary basin: In sedimentology, an area thickly filled with sediment in which the weight of the sediment further depresses the floor of the basin.

Structural or tectonic-related:

• Structural basin: A syncline-like depression; a region of tectonic downwarping as a result of isostasy (the Hawaiian Trough is an example) or subduction (such as the Chilean Central Valley).
• Graben or rift valley: down dropped and typically linear depressions or basin created by rifting in a region under tensional tectonic forces.
• Pull-apart basin caused by offset in a strike slip or transform fault (example: the Dead Sea area).
• Oceanic trench: a deep linear depression located in the ocean floor. Oceanic trenches are caused by the subduction (when one tectonic plate is pushed underneath another) of oceanic crust beneath either other oceanic crust or continental crust.
• A basin formed by ice sheet: an area depressed by the weight of the ice sheet resulting in post-glacial rebound after the ice melts (the area adjacent to the ice sheet may be pulled down to create a peripheral depression.)

Volcanism-related:

• Caldera: a volcanic depression resulting from collapse following a volcanic eruption.
• Pit crater: a volcanic depression smaller than a caldera formed by a sinking, or caving in, of the ground surface lying over a void.
• Maar: a depression resulting from phreatomagmatic eruption or diatreme explosion.

Depression, one of the most commonly diagnosed psychiatric disorders, is being diagnosed in increasing numbers in various segments of the population worldwide. Depression in the United States alone affects 17.6 million Americans each year or 1 in 6 people. Depressed patients are at increased risk of type 2 diabetes, cardiovascular disease and suicide. Within the next twenty years depression is expected to become the second leading cause of disability worldwide and the leading cause in high-income nations, including the United States. In approximately 75% of completed suicides, the individuals had seen a physician within the prior year before their death, 45%-66% within the prior month. About a third of those who completed suicide had contact with mental health services in the prior year, a fifth within the preceding month.

There are many psychiatric and medical conditions that may mimic some or all of the symptoms of depression or may occur comorbid to it. A disorder either psychiatric or medical that shares symptoms and characteristics of another disorder, and may be the true cause of the presenting symptoms is known as a differential diagnosis.Merriam-Webster's Medical Dictionary, Merriam-Webster, Inc.

• differential diagnosis definition: the distinguishing of a disease or condition from others presenting similar symptoms

Many psychiatric disorders such as depression are diagnosed by allied health professionals with little or no medical training, and are made on the basis of presenting symptoms without proper consideration of the underlying cause, adequate screening of differential diagnoses is often not conducted. According to one study, "non-medical mental health care providers may be at increased risk of not recognizing masked medical illnesses in their patients."

Misdiagnosis or missed diagnoses may lead to lack of treatment or ineffective and potentially harmful treatment which may worsen the underlying causative disorder. A conservative estimate is that 10% of all psychological symptoms may be due to medical reasons, with the results of one study suggesting that about half of individuals with a serious mental illness "have general medical conditions that are largely undiagnosed and untreated and may cause or exacerbate psychiatric symptoms."

In a case of misdiagnosed depression recounted in Newsweek, a writer received treatment for depression for years; during the last 10 years of her depression the symptoms worsened, resulting in multiple suicide attempts and psychiatric hospitalizations. When an MRI finally was performed, it showed the presence of a tumor. However, she was told by a neurologist that it was benign. After a worsening of symptoms, and upon the second opinion of another neurologist, the tumor was removed. After the surgery, she no longer suffered from depressive symptoms.