Depression is a serious
medical condition. In contrast to the normal
emotional experiences of sadness, loss, or passing mood states, clinical
depression is persistent and can interfere significantly with an
individual's ability to function. There are three main types of
depressive
disorders: major depressive disorder, dysthymic disorder, and bipolar
disorder (manic-depressive illness).
Symptoms and Types of Depression
Symptoms of depression include sad mood, loss of interest or
pleasure in
activities that were once enjoyed, change in appetite or weight,
difficulty
sleeping or oversleeping, physical slowing or agitation, energy loss,
feelings of worthlessness or inappropriate guilt, difficulty thinking or
concentrating, and recurrent thoughts of death or suicide. A diagnosis
of
major depressive disorder is made if a person has 5 or more of these
symptoms and impairment in usual functioning nearly every day during the
same two-week period. Major depression often begins between ages 15 to
30
but also can appear in children. 1 Episodes typically recur.
Some people have a chronic but less severe form of depression, called
dysthymic disorder, which is diagnosed when depressed mood persists for
at
least 2 years (1 year in children) and is accompanied by at least 2
other
symptoms of depression. Many people with dysthymia develop major
depressive
episodes.
Episodes of depression also occur in people with bipolar disorder. In
this
disorder, depression alternates with mania, which is characterized by
abnormally and persistently elevated mood or irritability and symptoms
including overly-inflated self-esteem, decreased need for sleep,
increased
talkativeness, racing thoughts, distractibility, physical agitation, and
excessive risk taking. Because bipolar disorder requires different
treatment
than major depressive disorder or dysthymia, obtaining an accurate
diagnosis
is extremely important.
Facts About Depression
Major depression is the leading cause of disability in the U.S. and
worldwide. 2
Depressive disorders affect an estimated 9.5 percent of adult Americans
ages
18 and over in a given year, 3 or about 18.8 million people in 1998. 4
Nearly twice as many women (12 percent) as men (7 percent) are affected
by a
depressive disorder each year. 3
Depression can be devastating to family relationships, friendships, and
the
ability to work or go to school. Many people still believe that the
emotional symptoms caused by depression are "not real," and that a
person
should be able to shake off the symptoms. Because of these inaccurate
beliefs, people with depression either may not recognize that they have
a
treatable disorder or may be discouraged from seeking or staying on
treatment due to feelings of shame and stigma. Too often, untreated or
inadequately treated depression is associated with suicide. 5
Treatments
Antidepressant medications are widely used, effective treatments for
depression. 6 Existing antidepressants influence the functioning of
certain
chemicals in the brain called neurotransmitters. The newer medications,
such
as the selective serotonin reuptake inhibitors (SSRIs), tend to have
fewer
side effects than the older drugs, which include tricyclic
antidepressants
(TCAs) and monoamine oxidase inhibitors (MAOIs). Although both
generations
of medications are effective in relieving depression, some people will
respond to one type of drug, but not another. Other types of
antidepressants
are now in development.
Certain types of psychotherapy, specifically cognitive-behavioral
therapy
(CBT) and interpersonal therapy (IPT), have been found helpful for
depression. Research indicates that mild to moderate depression often
can be
treated successfully with either therapy alone; however, severe
depression
appears more likely to respond to a combination of psychotherapy and
medication. 7 More than 80 percent of people with depressive disorders
improve when they receive appropriate treatment. 8
In situations where medication, psychotherapy, and the combination of
these
interventions prove ineffective, or work too slowly to relieve severe
symptoms such as psychosis (e.g., hallucinations, delusional thinking)
or
suicidality, electroconvulsive therapy (ECT) may be considered. ECT is a
highly effective treatment for severe depressive episodes. The
possibility
of long-lasting memory problems, although a concern in the past, has
been
significantly reduced with modern ECT techniques. However, the potential
benefits and risks of ECT, and of available alternative interventions,
should be carefully reviewed and discussed with individuals considering
this
treatment and, where appropriate, with family or friends. 9
One herbal supplement, hypericum or St. John's wort, has been promoted
as
having antidepressant properties. Results from the first large-scale,
controlled study of St. John's wort for major depression, which was
funded
in part by NIMH, are expected in 2001. Note: There is evidence that St.
John's Wort can reduce the effectiveness of certain medications. Use of
any
herbal or natural supplements should always be discussed with your
doctor
before they are tried.
Research Findings
Brain imaging research is revealing that in depression, neural circuits
responsible for moods, thinking, sleep, appetite, and behavior fail to
function properly, and that the regulation of critical neurotransmitters
is
impaired. 10
Genetics research, including studies of twins, indicates that genes play
a
role in depression. Vulnerability to depression appears to result from
the
influence of multiple genes acting together with environmental factors.
11
Other research has shown that stressful life events, particularly in the
form of loss such as the death of a close family member, may trigger
major
depression in susceptible individuals. 12
The hypothalamic-pituitary-adrenal (HPA) axis, the hormonal system that
regulates the body's response to stress, is overactive in many people
with
depression. Research findings suggest that persistent overactivation of
this
system may lay the groundwork for depression. 13
Studies of brain chemistry, mechanisms of action of antidepressant
medications, and the cognitive distortions and disturbed interpersonal
relationships commonly associated with depression, continue to inform
the
development of new and better treatments.
1 Birmaher B, Ryan ND, Williamson DE, et al. Childhood and adolescent
depression: a review of the past 10 years. Part I. Journal of the
American
Academy of Child and Adolescent Psychiatry, 1996; 35(11): 1427-39.
2 Murray CJL, Lopez AD, eds. Summary: The global burden of disease: a
comprehensive assessment of mortality and disability from diseases,
injuries, and risk factors in 1990 and projected to 2020. Cambridge, MA:
Published by the Harvard School of Public Health on behalf of the World
Health Organization and the World Bank, Harvard University Press, 1996.
3 Regier DA, Narrow WE, Rae DS, et al. The de facto mental and addictive
disorders service system. Epidemiologic Catchment Area prospective
1-year
prevalence rates of disorders and services. Archives of General
Psychiatry,
1993; 50(2): 85-94.
4 Narrow WE. One-year prevalence of depressive disorders among adults 18
and
over in the U.S.: NIMH ECA prospective data. Population estimates based
on
U.S. Census estimated residential population age 18 and over on July 1,
1998. Unpublished.
5 Conwell Y, Brent D. Suicide and aging I: patterns of psychiatric
diagnosis. International Psychogeriatrics, 1995; 7(2): 149-64.
6 Mulrow CD, Williams JW Jr., Trivedi M, et al. Evidence report on
treatment
of depression-newer pharmacotherapies. Psychopharmacology Bulletin,
1998;
34(4): 409-795.
7 Hyman SE, Rudorfer MV. Depressive and bipolar mood disorders. In: Dale
DC,
Federman DD, eds. Scientific American® Medicine. Volume 3. New York:
Healtheon/WebMD Corp., 2000, Sect. 13, Subsect. II, p. 1.
8 National Advisory Mental Health Council. Health care reform for
Americans
with severe mental illnesses. American Journal of Psychiatry, 1993;
150(10):
1447-65.
9 U.S. Department of Health and Human Services. Mental health: a report
of
the Surgeon General. Rockville, MD: U.S. Department of Health and Human
Services, Substance Abuse and Mental Health Services Administration,
Center
for Mental Health Services, National Institutes of Health, National
Institute of Mental Health, 1999.
10 Soares JC, Mann JJ. The functional neuroanatomy of mood disorders.
Journal of Psychiatric Research, 1997; 31(4): 393-432.
11 NIMH Genetics Workgroup. Genetics and mental disorders. NIH
Publication
No. 98-4268. Rockville, MD: National Institute of Mental Health, 1998.
12 Mazure CM, Bruce ML, Maciejewski PW, et al. Adverse life events and
cognitive-personality characteristics in the prediction of major
depression
and antidepressant response. American Journal of Psychiatry, 2000;
157(6):
896-903.
13 Arborelius L, Owens MJ, Plotsky PM, et al. The role of
corticotropin-releasing factor in depression and anxiety disorders.
Journal
of Endocrinology, 1999; 160(1): 1-12.
