Depression (psychology)
Depression
(psychology) is a mental illness in which a person
experiences deep, unshakable sadness and diminished interest in nearly
all
activities. People also use the term depression to describe the
temporary sadness, loneliness, or blues that everyone feels from time to
time.
In contrast to normal sadness, severe depression, also called major
depression, can dramatically impair a person’s ability to function
in
social situations and at work. People with major depression often have
feelings
of despair, hopelessness, and worthlessness, as well as thoughts of
committing
suicide.
Depression can take several
other
forms. In bipolar disorder, sometimes called manic-depressive
illness,
a person’s mood swings back and forth between depression and mania.
People with
seasonal affective disorder typically suffer from depression only during
autumn
and winter, when there are fewer hours of daylight. In dysthymia
(pronounced dis-THI-mee-uh), people feel depressed, have low
self-esteem, and
concentrate poorly most of the time—often for a period of years—but
their
symptoms are milder than in major depression. Some people with dysthymia
experience occasional episodes of major depression. Mental health
professionals
use the term clinical depression to refer to any of the above
forms of
depression.
Surveys indicate that
people commonly view depression as a sign of personal weakness, but
psychiatrists and psychologists view it as a real illness. In the United
States, the National Institute of Mental Health has estimated that
depression
costs society many billions of dollars each year, mostly in lost work
time.
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PREVALENCE
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Depression is one of the
most
common mental illnesses. At least 8 percent of adults in the United
States
experience serious depression at some point during their lives, and
estimates
range as high as 17 percent. The illness affects all people, regardless
of sex,
race, ethnicity, or socioeconomic standing. However, women are two to
three
times more likely than men to suffer from depression. Experts disagree
on the
reason for this difference. Some cite differences in hormones, and
others point
to the stress caused by society’s expectations of women.
Depression occurs in all
parts
of the world, although the pattern of symptoms can vary. The prevalence
of depression in other countries varies widely, from 1.5 percent of
people in
Taiwan to 19 percent of people in Lebanon. Some researchers believe
methods of
gathering data on depression account for different rates.
A number of large-scale
studies
indicate that depression rates have increased worldwide over the past
several decades. Furthermore, younger generations are experiencing
depression
at an earlier age than did previous generations. Social scientists have
proposed many explanations, including changes in family structure,
urbanization, and reduced cultural and religious influences.
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SYMPTOMS
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Although it may appear
anytime
from childhood to old age, depression usually begins during a person’s
20s or 30s. The illness may come on slowly, then deepen gradually over
months
or years. On the other hand, it may erupt suddenly in a few weeks or
days. A
person who develops severe depression may appear so confused,
frightened, and
unbalanced that observers speak of a “nervous breakdown.” However it
begins,
depression causes serious changes in a person’s feelings and outlook. A
person
with major depression feels sad nearly every day and may cry often.
People,
work, and activities that used to bring them pleasure no longer do.
Symptoms of depression
can
vary by age. In younger children, depression may include physical
complaints, such as stomachaches and headaches, as well as irritability,
“moping around,” social withdrawal, and changes in eating habits. They
may feel
unenthusiastic about school and other activities. In adolescents, common
symptoms include sad mood, sleep disturbances, and lack of energy.
Elderly
people with depression usually complain of physical rather than
emotional
problems, which sometimes leads doctors to misdiagnose the illness.
Symptoms of depression
can
also vary by culture. In some cultures, depressed people may not
experience
sadness or guilt but may complain of physical problems. In Mediterranean
cultures, for example, depressed people may complain of headaches or
nerves. In
Asian cultures they may complain of weakness, fatigue, or imbalance.
If left untreated, an
episode of major depression typically lasts eight or nine months. About
85
percent of people who experience one bout of depression will experience
future
episodes.
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Appetite and
Sleep
Changes
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Depression usually alters
a
person’s appetite, sometimes increasing it, but usually reducing it.
Sleep
habits often change as well. People with depression may oversleep or,
more
commonly, sleep for fewer hours. A depressed person might go to sleep at
midnight, sleep restlessly, then wake up at 5 am
feeling tired and blue. For many depressed people, early morning is the
saddest
time of the day.
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Changes in
Energy Level
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Depression also changes
one’s
energy level. Some depressed people may be restless and agitated,
engaging in fidgety movements and pacing. Others may feel sluggish and
inactive, experiencing great fatigue, lack of energy, and a feeling of
being
worn out or carrying a heavy burden. Depressed people may also have
difficulty
thinking, poor concentration, and problems with memory.
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Poor Self-Esteem
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People with depression
often
experience feelings of worthlessness, helplessness, guilt, and
self-blame. They may interpret a minor failing on their part as a sign
of
incompetence or interpret minor criticism as condemnation. Some
depressed
people complain of being spiritually or morally dead. The mirror seems
to
reflect someone ugly and repulsive. Even a competent and decent person
may feel
deficient, cruel, stupid, phony, or guilty of having deceived others.
People
with major depression may experience such extreme emotional pain that
they consider
or attempt suicide. At least 15 percent of seriously depressed people
commit
suicide, and many more attempt it.
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Psychotic
Symptoms
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In some cases, people
with depression may experience psychotic symptoms, such as delusions
(false
beliefs) and hallucinations (false sensory perceptions). Psychotic
symptoms
indicate an especially severe illness. Compared to other depressed
people,
those with psychotic symptoms have longer hospital stays, and after
leaving,
they are more likely to be moody and unhappy. They are also more likely
to
commit suicide. See Psychosis.
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CAUSES
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Some depressions seem
to come out of the blue, even when things are going well. Others seem to
have
an obvious cause: a marital conflict, financial difficulty, or some
personal
failure. Yet many people with these problems do not become deeply
depressed.
Most psychologists believe depression results from an interaction
between
stressful life events and a person’s biological and psychological
vulnerabilities.
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Biological
Factors
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Depression runs in families.
By
studying twins, researchers have found evidence of a strong genetic
influence in depression. Genetically identical twins raised in the same
environment are three times more likely to have depression in common
than
fraternal twins, who have only about half of their genes in common. In
addition, identical twins are five times more likely to have bipolar
disorder
in common. These findings suggest that vulnerability to depression and
bipolar
disorder can be inherited. Adoption studies have provided more evidence
of a
genetic role in depression. These studies show that children of
depressed
people are vulnerable to depression even when raised by adoptive
parents.
Genes may influence depression
by
causing abnormal activity in the brain. Studies have shown that certain
brain chemicals called neurotransmitters play an important role in
regulating
moods and emotions. Neurotransmitters involved in depression include
norepinephrine, dopamine, and serotonin. Research in the 1960s suggested
that
depression results from lower than normal levels of these
neurotransmitters in
parts of the brain. Support for this theory came from the effects of
antidepressant drugs, which work by increasing the levels of
neurotransmitters
involved in depression. However, later studies have discredited this
simple
explanation and have suggested a more complex relationship between
neurotransmitter levels and depression.
An imbalance of hormones
may
also play a role in depression. Many depressed people have higher than
normal levels of hydrocortisone (cortisol), a hormone secreted by the
adrenal
gland in response to stress. In addition, an underactive or overactive
thyroid
gland can lead to depression.
A variety of medical conditions
can
cause depression. These include dietary deficiences in vitamin B6,
vitamin B12, and folic acid (see Vitamin);
degenerative
neurological disorders, such as Alzheimer’s disease and Huntington’s
disease (see
Chorea); strokes in the frontal part of the brain; and certain viral
infections, such as hepatitis and mononucleosis. Certain medications,
such as
steroids, may also cause depression.
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Psychological
Factors
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Psychological theories
of
depression focus on the way people think and behave. In a 1917 essay,
Austrian psychoanalyst Sigmund Freud explained melancholia, or
major
depression, as a response to loss—either real loss, such as the death of
a
spouse, or symbolic loss, such as the failure to achieve an important
goal.
Freud believed that a person’s unconscious anger over loss weakens the
ego,
resulting in self-hate and self-destructive behavior.
Cognitive theories of
depression emphasize the role of irrational thought processes. American
psychiatrist Aaron Beck proposed that depressed people tend to view
themselves,
their environment, and the future in a negative light because of errors
in
thinking. These errors include focusing on the negative aspects of any
situation, misinterpreting facts in negative ways, and blaming
themselves for
any misfortune. In Beck’s view, people learn these self-defeating ways
of
looking at the world during early childhood. This negative thinking
makes
situations seem much worse than they really are and increases the risk
of depression,
especially in stressful situations.
In support of this cognitive
view,
people with “depressive” personality traits appear to be more
vulnerable
than others to actual depression. Examples of depressive personality
traits
include gloominess, pessimism, introversion, self-criticism, excessive
skepticism and criticism of others, deep feelings of inadequacy, and
excessive
brooding and worrying. In addition, people who regularly behave in
dependent,
hostile, and impulsive ways appear at greater risk for depression.
American psychologist
Martin Seligman proposed that depression stems from “learned
helplessness,” an
acquired belief that one cannot control the outcome of events. In this
view,
prolonged exposure to uncontrollable and inescapable events leads to
apathy,
pessimism, and loss of motivation. An adaptation of this theory by
American
psychologist Lynn Abramson and her colleagues argues that depression
results
not only from helplessness, but also from hopelessness. The hopelessness
theory
attributes depression to a pattern of negative thinking in which people
blame
themselves for negative life events, view the causes of those events as
permanent, and overgeneralize specific weaknesses as applying to many
areas of
their life.
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Stressful Events
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Psychologists agree that
stressful
experiences can trigger depression in people who are predisposed to
the illness. For example, the death of a loved one may trigger
depression.
Psychologists usually distinguish true depression from grief, a
normal
process of mourning a loved one who has died. Other stressful
experiences may
include divorce, pregnancy, the loss of a job, and even childbirth.
About 20
percent of women experience an episode of depression, known as postpartum
depression, after having a baby. In addition, people with serious
physical
illnesses or disabilities often develop depression.
People who experience
child abuse appear more vulnerable to depression than others. So, too,
do
people living under chronically stressful conditions, such as single
mothers
with many children and little or no support from friends or relatives.
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TREATMENT
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Depression typically cannot
be
shaken or willed away. An episode must therefore run its course until
it
weakens either on its own or with treatment. Depression can be treated
effectively with antidepressant drugs, psychotherapy, or a combination
of both.
Despite the availability
of
effective treatment, most depressive disorders go untreated and
undiagnosed.
Studies indicate that general physicians fail to recognize depression in
their
patients at least half of the time. In addition, many doctors and
patients view
depression in elderly people as a normal part of aging, even though
treatment
for depression in older people is usually very effective.
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Antidepressant
Drugs
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Up to 70 percent of people
with
depression respond to antidepressant drugs. These medications appear to
work by altering the levels of serotonin, norepinephrine, and other
neurotransmitters in the brain. They generally take at least two to
three weeks
to become effective. Doctors cannot predict which type of antidepressant
drug
will work best for any particular person, so depressed people may need
to try
several types. Antidepressant drugs are not addictive, but they may
produce
unwanted side effects. To avoid relapse, people usually must continue
taking
the medication for several months after their symptoms improve.
Commonly used antidepressant
drugs
fall into three major classes: tricyclics, monoamine oxidase inhibitors
(MAO inhibitors), and selective serotonin reuptake inhibitors (SSRIs). Tricyclics,
named for their three-ring chemical structure, include amitriptyline
(Elavil),
imipramine (Tofanil), desipramine (Norpramin), doxepin (Sinequan), and
nortriptyline
(Pamelor). Side effects of tricyclics may include drowsiness, dizziness
upon
standing, blurred vision, nausea, insomnia, constipation, and dry mouth.
MAO inhibitors include
isocarboxazid (Marplan), phenelzine (Nardil), and
tranylcypromine (Parnate). People who take MAO inhibitors must follow a
diet
that excludes tyramine—a substance found in wine, beer, some cheeses,
and many
fermented foods—to avoid a dangerous rise in blood pressure. In
addition, MAO
inhibitors have many of the same side effects as tricyclics.
Selective serotonin reuptake
inhibitors
include
fluoxetine (Prozac), sertraline (Zoloft), and paroxetine (Paxil). These
drugs
generally produce fewer and milder side effects than do other types of
antidepressants, although SSRIs may cause anxiety, insomnia, drowsiness,
headaches, and sexual dysfunction. Some patients have alleged that
Prozac
causes violent or suicidal behavior in a small number of cases, but the
U.S.
Food and Drug Administration has failed to substantiate this claim.
Prozac became the most
widely
used antidepressant in the world soon after its introduction in the
late
1980s by drug manufacturer Eli Lilly and Company. Many people find
Prozac
extremely effective in lifting depression. In addition, some people have
reported that Prozac actually tranforms their personality by increasing
their
self-confidence, optimism, and energy level. However, mental health
professionals have expressed serious ethical concerns over Prozac’s use
as a
“personality enhancer,” especially among people without clinical
depression.
Doctors often prescribe
lithium
carbonate, a natural mineral salt, to treat people with bipolar
disorder (see Lithium). People often take lithium during periods
of
relatively normal mood to delay or even prevent subsequent mood swings.
Side
effects of lithium include nausea, stomach upset, vertigo, and frequent
urination.
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Psychotherapy
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Studies have shown that
short-term
psychotherapy can relieve mild to moderate depression as effectively
as antidepressant drugs. Unlike medication, psychotherapy produces no
physiological side effects. In addition, depressed people treated with
psychotherapy appear less likely to experience a relapse than those
treated
only with antidepressant medication. However, psychotherapy usually
takes
longer to produce benefits.
There are many kinds of
psychotherapy.
Cognitive-behavioral therapy assumes that depression
stems from negative, often irrational thinking about oneself and one’s
future.
In this type of therapy, a person learns to understand and eventually
eliminate
those habits of negative thinking. In interpersonal therapy, the
therapist helps a person resolve problems in relationships with others
that may
have caused the depression. The subsequent improvement in social
relationships
and support helps alleviate the depression. Psychodynamic therapy
views
depression as the result of internal, unconscious conflicts.
Psychodynamic
therapists focus on a person’s past experiences and the resolution of
childhood
conflicts. Psychoanalysis is an example of this type of therapy. Critics
of
long-term psychodynamic therapy argue that its effectiveness is
scientifically
unproven.
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Other Treatments
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Electroconvulsive therapy
(ECT)
can often relieve severe depression in people who fail to respond to
antidepressant medication and psychotherapy. In this type of therapy, a
low-voltage electric current is passed through the brain for one to two
seconds
to produce a controlled seizure. Patients usually receive six to ten ECT
treatments over several weeks. ECT remains controversial because it can
cause
disorientation and memory loss. Nevertheless, research has found it
highly
effective in alleviating severe depression.
For milder cases of depression,
regular
aerobic exercise may improve mood as effectively as psychotherapy or
medication. In addition, some research indicates that dietary
modifications can
influence one’s mood by changing the level of serotonin in the brain.
Tags
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