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Seasonal Affective Disorder

Seasonal affective disorder

Definition

Seasonal affective disorder (SAD) is a form of depression most often associated with lack of daylight in extreme northern and southern latitudes from the late fall to the early spring.

Description

Although researchers are not certain what causes seasonal affective disorder, they suspect that it has something to do with the hormone melatonin . Melatonin is thought to play an active role in regulating the "internal body clock," which dictates when humans feel like going to bed at night and getting up in the morning. Although seasonal affective disorder is most common when light is low, it may occur in the spring, which is often called reverse or spring-onset SAD. Recent research also indicates that SAD has a genetic factor; about 29% of cases in the United States run in families.

Causes & symptoms

The body produces more melatonin at night than during the day, and scientists believe it helps people feel sleepy at nighttime. There is also more melatonin in the body during winter, when the days are shorter. Some researchers believe that excessive melatonin release during winter in people with SAD may account for their feelings of drowsiness or depression. One variation on this idea is that people's internal clocks may become out of sync during winter with the light-dark cycle, leading to a long-term disruption in melatonin release. Another possible cause of SAD is that people may not adjust their habits to the season, or sleep more hours when it is darker, as would be natural.

Seasonal affective disorder, while not an official category of mental illness listed by the American Psychiatric

SYMPTOMS OF SEASONAL AFFECTIVE DISORDER (SAD)
Increased sleep
Depression
Lethargy
Weight gain
Carbohydrate cravings
Decreased sex drive
Avoidance of social interaction
Difficulty performing daily tasks
Crying fits
Suicidal thoughts

Association, is estimated to affect 6% of the American population. Another 25 million Americans may have a mild form of SAD, sometimes called the "winter blues" or "winter blahs." The risk of SAD increases the further from the equator a person lives; one early study of SAD found a 1.4% incidence of the disorder among people living in Florida, compared with 9.7% among residents of New Hampshire. Other factors that influence the incidence and severity of SAD are sex and age. Women are more likely than men to develop SAD, but men with the disorder are more severely depressed than most women who have it. SAD appears to decrease in severity with age; the elderly have milder SAD symptoms than adolescents.

Comparative studies indicate that the incidence of SAD in the United States and Canada is about twice as high as in European countries at the same latitudes north of the Equator. These findings suggest that cultural factors are also involved in the disorder.

The symptoms of SAD are similar to those of other forms of depression. People with SAD may feel sad, irritable, or tired, and may find themselves sleeping too much. They may also lose interest in normal or pleasurable activities (including sex), become withdrawn, crave carbohydrates, and gain weight.

Diagnosis

Doctors usually diagnose seasonal affective disorder based on the patient's description of symptoms, including the time of year they occur. There is also a diagnostic questionnaire called the Seasonal Pattern Assessment Questionnaire, or SPAQ, used in all Canadian university hospitals and widely used in the United States to assess SAD patients.

Treatment

The first-line treatment for seasonal affective disorder is light therapy (also known as phototherapy). The most commonly used phototherapy equipment is a portable lighting device known as a light box. The box may be mounted upright to a wall or slanted downward toward a table. The patient sits in front of the box for a pre-prescribed period of time (anywhere from 15 minutes to several hours). Some patients with SAD undergo light therapy sessions two or three times daily, others only once. The time of day and the number of times treatment is administered depend on the physical needs and lifestyle of the patient. Light therapy treatment for SAD typically begins in the fall as the days begin to shorten, and continues throughout the winter and possibly the early spring.

The light from a slanted light box is designed to fall on the table supporting the box, so patients may look down to read or do other sedentary activities during therapy. Patients using an upright light box must face the light source (although they need not look directly into the light). The light sources in these light boxes typically range from 2,500 to 10,000 lux (in contrast, average indoor lighting is 300 to 500 lux; a sunny summer day is about 100,000 lux).

A recent British study suggests that dawn simulation, a form of light therapy in which the patient is exposed to white light of gradually increasing brightness (peaking at 250 lux after 90 min) may be even more effective in treating SAD than exposure to bright light. Dawn simulation is started around 4:30 or 5 o'clock in the morning while the patient is still asleep.

Patients with eye problems should see an ophthalmologist regularly both before and during light therapy. Because some UV rays are emitted by the light boxes used in phototherapy, patients taking photosensitizing medications and those who have sun-sensitive skin should consult with a health care professional before beginning treatment. Patients with medical conditions that make them sensitive to UV rays should also see a doctor before starting phototherapy.

Light therapy appears to be safe for most people. However, it can cause side effects of eyestrain, headaches, insomnia, fatigue, sunburn , and dry eyes and nose in some patients. Most of these effects can be managed by adjusting the timing and duration of light therapy sessions. A strong sun block and eye and nose drops can alleviate the others.

Recently, researchers have begun testing whether people who do not completely respond to light therapy can benefit from tiny doses of the hormone melatonin to reset the body's internal clock. Early results look promising, but the potential benefits must be confirmed in larger studies before this type of treatment becomes widely accepted.

Allopathic treatment

Like other types of mood disorders, seasonal affective disorder may also respond to medication and psychotherapy . Common drugs prescribed for mood disorders are:

  • Selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine (Prozac), paroxetine (Paxil), and sertraline (Zoloft)
  • Monoamine oxidase inhibitors (MAO inhibitors), such as phenelzine sulfate (Nardil) and tranylcypromine sulfate (Parnate)
  • Lithium salts, such as lithium carbonate (Eskalith), often used in people with bipolar mood disorders, are often useful with SAD patients who also suffer from bipolar disorder (excessive mood swings; formerly known as manic depression)

A number of psychotherapy approaches are useful as well. Interpersonal psychotherapy helps patients recognize how their mood disorder and their interpersonal relationships interact. Cognitive-behavioral therapy explores how the patient's view of the world may be affecting mood and outlook.

A new treatment for SAD that is still in the experimental phase as of 2001 is the use of high-density negative air ionization.

Expected results

Most patients with seasonal affective disorder respond to light therapy, dawn simulation, and/or antidepressant drugs. Others respond to sleeping more hours in a dark room. Some researchers estimate that as much as 9.5 hours of sleep are important in winter months and that getting more sleep will increase the person's levels of natural melatonin.

Resources

BOOKS

Lam, Raymond, ed. Seasonal Affective Disorder and Beyond: Light Treatment for SAD and Non-SAD Conditions. Washington, DC: American Psychiatric Press, 1998.

Partonen, Timo, and Andres Magnusson, eds. Seasonal Affective Disorder: Practice and Research. Oxford, UK: Oxford University Press, 2001.

Peters, Celeste A. Don't Be SAD: Your Guide to Conquering Seasonal Affective Disorder. Calgary, Alberta: Good Health Books, 1994.

Rosenthal, Norman. Winter Blues: Seasonal Affective DisorderWhat It Is and How to Overcome It. New York: Guilford Press, 1998.

PERIODICALS

Anderson, Janis L., and Gabrielle I. Warner. "Seasonal Depression." Harvard Health Letter (February 1996): 7-8.

Eagles, John M. "SADHelp arrives with the dawn?" Lancet 358 (December 22, 2001): 2100.

Singer, Ethan A. "Seasonal Affective Disorder: Autumn Onset, Winter Gloom." Clinician Reviews 11 (November 2001): 49-54.

"Winter Depression: Seeing the Light." The University of California Berkeley Wellness Letter (November 1996): 4.

ORGANIZATIONS

National Depressive and Manic Depressive Association. 730 N. Franklin Street, Ste. 501, Chicago, IL 60610. (312) 642-0049.

National Institute of Mental Health. Mental Health Public Inquiries, 5600 Fishers Lane, Room 15C-05, Rockville, MD 20857. (301) 443-4513. (888) 826-9438. <http://www.nimh.nih.gov>.

Society for Light Treatment and Biological Rhythms. 824 Howard Ave., New Haven, CT 06519. Fax (203) 764-4324. <http://www.sltbr.org.sltbr@yale.edu>.

Paula Ford-Martin

Rebecca J. Frey, PhD

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Seasonal affective disorder

Seasonal affective disorder

Definition

Seasonal affective disorder, often abbreviated as SAD, is a type of mood disorder that follows an annual pattern consistent with the seasons. The most common course for SAD includes an onset of depressive symptoms late in the fall, continuation of symptoms throughout winter, and remission of symptoms in the spring.

Description

According to the handbook used by mental health professionals to diagnose mental disorders, the Diagnostic and Statistical Manual of Mental Disorders fourth edition text revised, or DSM-IV-TR, SAD is not considered a disorder or syndrome on its own. Instead, SAD is considered a pattern specifier, or subtype, of another mood disorder diagnosis . For example, an individual may be diagnosed as having a major depressive episode with a seasonal pattern.

The most common type of seasonal pattern is one in which an individual first experiences symptoms in the late fall, has continued and heightened symptoms in winter, and then experiences a remission of symptoms in the spring. However, other patterns are possible. For example, a person may become depressed in the summer and then become less depressed when the weather becomes colder.

Causes and symptoms

Causes

Lack of sunlight, normally associated with winter, is considered to be the primary cause of SAD. Although winter temperature may also have an impact, especially in colder areas, the lack of light is most important. This is supported by the effectiveness of therapy in which individuals are exposed to high-intensity light (light therapy ). The causes of rarer types of seasonal symptoms, such as those experienced by individuals who become depressed in summer, are more difficult to determine.

Symptoms

The symptoms experienced by people with SAD are similar to some of those experienced by depressed people in general: change in appetite, weight gain or loss, fatigue , reduced energy, irritability, and avoidance of social situations. To meet the diagnostic criteria for the disorder as indicated in the DSM-IV-TR, these symptoms must be present during the season the individual is depressed and must lessen or abate when that season is over.

Demographics

Some studies have shown that up to 6% of people experience some depressive symptoms in winter. SAD is a more common phenomenon in women than men. According to the DSM-IV-TR, women make up 6090% of people with the seasonal pattern of depression. SAD primarily affects adults, although it is possible for children and adolescents to suffer from it. Research indicates that SAD is much more common in countries and regions where there are distinct seasonal changes. In countries near the equator, where changes in climate and light are mild, SAD generally does not occur.

Diagnosis

SAD is diagnosed through a clinical interview with the patient and careful history-taking by the physician. For the seasonal pattern specifier to be applied to a DSM-IV-TR mood disorder diagnosis, the following criteria must be met: there is a relationship between the onset of the depressive episode and a particular time of year; the depressive symptoms are in remission at a particular time of year; the onset and remissions have occurred at these times for the past two years; and seasonal depressive episodes outnumber non-seasonal depressive episodes over the person's lifetime. Also, the seasonal pattern specifier must not be given when depressive symptoms are due to seasonally linked stressors, such as the beginning of school or an employment schedule.

An individual with seasonal depression must be distinguished from one with who has depressive symptoms all year long.

Treatments

Light therapy, in which the person experiencing SAD is exposed to high-intensity light, is often usedusually for one to two hours per day. Sometimes, briefer periods of exposure to higher-intensity light can be used. The exposure to light may be facilitated through the use of a box which emits the prescribed light or through the use of a light visor the patient wears on his or her head. Tanning beds should not be used for light therapy. Light therapy has been found to be the most effective treatment for people correctly diagnosed with seasonal symptoms in the winter. It does not appear to have serious side effects.

Prognosis

Light therapy is considered to be a safe and effective treatment. However, it is time consuming and people do not always stay on the prescribed course of treatment. Also, SAD can be a persistent problem; even if light therapy is effective one year, symptoms may return the following year.

See also Bipolar disorders; Depressive disorders

Resources

BOOKS

American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 4th edition, text revision. Washington, DC: American Psychiatric Association, 2000.

Salkovskis, Paul. Comprehensive Clinical Psychology Volume 6: Adults: Clinical Formulation and Treatment. Amsterdam: Elsevier, 1998.

ORGANIZATIONS

Depression and Related Affective Disorders Association. 600 N. Wolfe St., Baltimore, MD, 21287. <http://www.drada.org>.

Seasonal Affective Disorder Association. PO Box 989, Steyning BN44 3HG, England. <http://www.sada.org.uk>.

Ali Fahmy, Ph.D.

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Seasonal Affective Disorder

Seasonal Affective Disorder

Definition

Seasonal affective disorder (SAD) is a form of depression most often associated with the lack of daylight in extreme northern and southern latitudes from the late fall to the early spring.

Description

Although researchers are not certain what causes seasonal affective disorder, they suspect that it has something to do with the hormone melatonin. Melatonin is thought to play an active role in regulating the "internal body clock," which dictates when humans feel like going to bed at night and getting up in the morning. Although seasonal affective disorder is most common when light is low, it may occur in the spring, and it is then often called reverse SAD.

Causes and symptoms

The body produces more melatonin at night than during the day, and scientists believe it helps people feel sleepy at nighttime. There is also more melatonin in the body during winter, when the days are shorter. Some researchers believe that excessive melatonin release during winter in people with SAD may account for their feelings of drowsiness or depression. One variation on this idea is that, during winter, people's internal clocks may become out of sync with the light-dark cycle, leading to a long-term disruption in melatonin release.

Seasonal affective disorder, while not an official category of mental illness listed by the American Psychiatric Association, is estimated to affect 10 million Americans, most of whom are women. Another 25 million Americans may have a mild form of SAD, sometimes called the "winter blues" or "winter blahs." The risk of SAD increases the further from the equator a person lives.

The symptoms of SAD are similar to those of other forms of depression. People with SAD may feel sad, irritable, or tired, and may find themselves sleeping too much. They may also lose interest in normal or pleasurable activities (including sex), become withdrawn, crave carbohydrates, and gain weight.

Diagnosis

Doctors usually diagnose seasonal affective disorder based on the patient's description of symptoms, including the time of year they occur.

Treatment

The first-line treatment for seasonal affective disorder is light therapy, exposing the patient to bright artificial light to compensate for the gloominess of winter. Light therapy uses a device called a light box, which contains a set of fluorescent or incandescent lights in front of a reflector. Typically, the patient sits for 30 minutes next to a 10,000-lux box (which is about 50 times as bright as ordinary indoor light). Light therapy appears to be safe for most people. However, it may be harmful for those with eye diseases. The most common side effects are vision problems such as eye strain, headaches, irritability, and insomnia. In addition, hypomania (elevated or expansive mood, characterized by hyperactivity and inflated self esteem) may occasionally occur.

Recently, researchers have begun testing whether people who do not completely respond to light therapy can benefit from tiny doses of the hormone melatonin to reset the body's internal clock. Early results look promising, but the potential benefits must be confirmed in larger studies before this type of treatment becomes widely accepted.

Like other types of mood disorders, seasonal affective disorder may also respond to medication and psychotherapy. The four different classes of drugs used for mood disorders are:

  • heterocyclic antidepressants (HCAs), such as amitriptyline (Elavil)
  • selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine (Prozac), paroxetine (Paxil), and sertraline (Zoloft)
  • monoamine oxidase inhibitors (MAO inhibitors), such as phenelzine sulfate (Nardil) and tranylcypromine sulfate (Parnate)
  • Lithium salts, such as lithium carbonate (Eskalith), often used in people with bipolar mood disorders, are often useful with SAD patients; many SAD patients also suffer from bipolar disorder (excessive mood swings; formerly known as manic depression)

A number of psychotherapy approaches are useful as well. Interpersonal psychotherapy helps patients recognize how their mood disorder and their interpersonal relationships interact. Cognitive-behavioral therapy explores how the patient's view of the world may be affecting mood and outlook.

Prognosis

Most patients with seasonal affective disorder respond to light therapy and/or antidepressant drugs.

Resources

ORGANIZATIONS

American Psychiatric Association. 1400 K Street NW, Washington DC 20005. (888) 357-7924. http://www.psych.org.

National Depressive and Manic Depressive Association (NDMDA). 730 N. Franklin St., Ste. 501, Chicago, IL 60610. (800) 826-3632. http://www.ndmda.org.

National Institute of Mental Health. Mental Health Public Inquiries, 5600 Fishers Lane, Room 15C-05, Rockville, MD 20857. (888) 826-9438. http://www.nimh.nih.gov.

KEY TERMS

Cognitive behavioral therapy Psychotherapy aimed at helping people change their attitudes, perceptions, and patterns of thinking.

Melatonin A naturally occurring hormone involved in regulating the body's "internal clock."

Serotonin A chemical messenger in the brain thought to play a role in regulating mood.

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seasonal affective disorder

seasonal affective disorder (SAD), recurrent fall or winter depression characterized by excessive sleeping, social withdrawal, depression, overeating, and pronounced weight gain. SAD effects an estimated 6% of Americans; for reasons not yet understood, 80% of those affected are women. Most children who are affected have a close relative who also has SAD or another psychiatric condition. The disorder particularly affects people who live in the upper latitudes.

Although the mechanism of the disorder is not perfectly understood, it is known to be a reaction to the biological effects of light on the body (see biorhythm). Daily, or circadian, rhythms help animals keep track of the seasonal changes in the environment, such as the shortening of days in winter, so that they can make the adaptive changes necessary for their survival in each season. Two substances, the hormone melatonin and the neurotransmitter serotonin, are a part of this process and are being studied for a possible role in SAD. Melatonin is secreted by the pineal gland, which is in turn controlled by an area (the suprachiasmatic nuclei) of the hypothalamus; the hypothalamus, among other things, performs a clocklike function in the body. The eye's retinal nerves are connected to this area. Melatonin is secreted chiefly at night, and its secretion is suppressed by light. Secretion of the neurotransmitter serotonin declines in the winter and may undergo abnormal declines in those with SAD; concentrations of serotonin are increased by bright light. Serotonin is especially active in the hypothalamus. Decreased sensitivity of the retina has also been implicated as a cause of SAD.

Treatment with bright light (about five to twenty times brighter than normal lighting) often alleviates symptoms within a period of days. Unwieldy lighting paraphernalia has given way to smaller, portable light boxes and lighted visors. Doses range from 30 minutes to a few hours per day, often undergone in the morning to simulate the dawn.

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Seasonal Affective Disorder

SEASONAL AFFECTIVE DISORDER

DEFINITION


Seasonal affective disorder (SAD) is a form of depression (see depression entry) most often associated with the lack of daylight. The condition usually occurs in the extreme southern and northern latitudes from late fall to early spring.

DESCRIPTION


SAD occurs in parts of the world where days are very short during some seasons of the year. In Alaska and parts of Canada, for example, there may be no more than a few hours of daylight during the winter months. During these periods, some people may become very depressed. That condition is known as seasonal affective disorder, or SAD. When SAD occurs in the spring, when there is more daylight, it is sometimes called reverse SAD.

Though SAD is not officially listed as a mental disorder by psychiatrists, some authorities think as many as ten million Americans may be affected by the condition. Another twenty-five million Americans may have a mild form of SAD, called the "winter blues" or "winter blahs." The farther a person lives from the equator, the more likely he or she is to develop SAD. Women make up the majority of people with the disorder.

CAUSES


Scientists are not sure what causes SAD, but a hormone known as melatonin may be involved. A hormone is a chemical that occurs naturally in the body and controls certain body functions. Melatonin (pronounced mell-uh-TOE-nin) is thought to act as an internal body clock, "reminding" people when to go to bed at night and when to get up in the morning. If the hormone does not function properly, a person's body rhythms may be disturbed, which could lead to depression.

The amount of melatonin produced by the body is partly a function of the amount of daylight the body is exposed to. The more daylight, the less melatonin the body makes. The less daylight, the more melatonin. Scientists know that our bodies produce more melatonin at night and during the winter, when days are short.

One function of melatonin is to make the body feel sleepy. Some researchers think SAD is caused by an excess of melatonin during the winter months. People with too much melatonin may feel tired and depressed.

Seasonal Affective Disorder: Words to Know

Antidepressant:
A drug used to prevent or relieve depression.
Hormones:
Chemicals that occur naturally in the body and control certain body functions.
Melatonin:
A hormone thought to control the body's natural sleep rhythms.

SYMPTOMS


The symptoms of SAD are similar to those of other forms of depression. People with SAD may feel sad, irritable, or tired. They may find themselves sleeping too much. They may also lose interest in normal activities and become withdrawn. A tendency to overeat and gain weight is another common symptom of SAD.

DIAGNOSIS


One step in diagnosing SAD is to eliminate other possible causes of a person's depression. A doctor also relies on the patient's description of his or her own symptoms, including the time of the year in which they occur.

TREATMENT


One obvious way to treat SAD is to expose a patient to a greater amount of light. One device used for this purpose is a light box. A light box contains a set of lights in front of a reflector. The light produced by this device is about fifty times as bright as ordinary indoor light. The patient sits next to the light box for about thirty minutes each session. The light box replaces a portion of the natural light that is absent in the winter months.

Light therapy is generally considered safe for most people. However, it may be harmful to people with eye disorders. The most common side effects of using a light box are vision problems, such as eye strain; headaches; irritability; and insomnia. In addition, a person may experience an excited mood after using the light box.

NIELS TYBERG FINSEN

It's easy to take the common things in life for granted. Sunlight is an example. We are so used to seeing sunlight that we may not realize how important it is to health. For example, sunlight helps the production of vitamin D in the skin. Vitamin D prevents bone disease.

One of the first scientists to study the effects of light on health was Niels Tyberg Finsen (18601903). Finsen was born in the Faroe Islands in the North Atlantic Ocean. The Faroe Islands are close to the Arctic Circle. They receive relatively little sunshine throughout the year.

When Finsen became a doctor, he decided to study the effects of ultraviolet light on biological tissue. He became convinced that light can be used to treat human disease. He invented a powerful lamp for the treatment of lupus vulgaris, a skin disorder. The lamp was called the Finsen light in his honor.

Some of Finsen's ideas were incorrect. For example, he mistakenly thought that light could be used to cure smallpox. But, overall, his research was very important. It led the way to using many forms of radiation, including X rays and gamma rays, to treat human disorders. For his work in this field, Finsen was awarded the 1903 Nobel Prize in medicine and physiology.

Another possible treatment for SAD that is being studied is injections of melatonin. Some researchers think that the hormone might help the body adjust to longer periods of darkness without causing depression.

Seasonal affective disorder may also respond to medication. The four classes of drugs used for the disorder are:

  • Heterocyclic antidepressants (HCAs), such as amitriptyline (trade name Elavil)
  • Selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine (trade name Prozac), paroxetine (trade name Paxil), and sertraline (trade name Zoloft)
  • Monoamine oxidase inhibitors (MAO inhibitors), such as phenelzine sulfate (trade name Nardil) and tranylcypromine sulfate (trade name Parnate)
  • Lithium salts, such as lithium carbonate (trade name Eskalith), often used by people with bipolar disorder

Counseling

Counseling can sometimes help people with SAD, by helping patients understand the cause of their disorder and how it can affect their interaction with other people.

PROGNOSIS


Most patients with seasonal affective disorder respond to light therapy and/or medications.

PREVENTION


SAD can be prevented by increasing one's exposure to natural light.

FOR MORE INFORMATION


Books

Peters, Celeste A. Don't Be SAD: Your Guide to Conquering Seasonal Affective Disorder. Calgary, Alberta: Good Health Books, 1994.

Rosenthal, Norman E. Winter Blues: Seasonal Affective Disorder: What It Is and How to Overcome It. New York: Guilford Press, 1998.

Taylor, Clifford A., and Robin Karol Levinson. If You Think You Have Seasonal Affective Disorder. New York: Dell Publishing Company, 1998.

Organizations

American Psychiatric Association. 1400 K Street NW, Washington, DC 20005. (202) 6826000. http://www.psych.org.

National Depressive and Manic Depressive Association. 730 N. Franklin Street, Suite 501, Chicago, IL 60610. (312) 6420049.

National Institutes of Mental Health. Mental Health Public Inquiries. 5600 Fishers Lane, Room 15C-05, Rockville, MD 20857. (301) 4434513.(888) 8269438. http://www.nimh.nih.gov.

Web sites

"Ask NOAH About: Mental Health." NOAH: New York Online Access to Health. [Online] http://www.noah.cuny.edu/mentalhealth/mental.html#SAD (accessed on October 31, 1999).

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Seasonal Affective Disorder

Seasonal Affective Disorder

More Than the Winter Blahs

What Causes Seasonal Affective Disorder?

What Are the Symptoms of SAD?

How Is SAD Treated?

Resource

Seasonal affective disorder (SAD) is a form of depression that occurs at the same time each year (usually with the onset of winter) and disappears at the same time each year (typically at the start of spring). SAD is linked to the availability of daylight and is found most often in the Northern Hemisphere.

KEYWORDS

for searching the Internet and other reference sources

Depression

Disthymia

More Than the Winter Blahs

Many people get the winter blahs or cabin fever as the days get shorter and colder, but for about 10 million Americans with SAD, shorter days mean a slide into true depression. SAD is a seasonal pattern of depression. It occurs in about 5 of every 100 people. Four times more women than men experience SAD, and it can also occur in children and teens. The farther away from the equator someone lives, the higher the risk that he or she will experience SAD. One study has estimated the incidence of SAD in the general population as only 1.4 percent in Florida but 9.7 percent in New Hampshire. This comparison suggests that in the southern United States only about 1 person in 100 has this condition, but in the north, the number may be as high as 1 in 10 people.

What Causes Seasonal Affective Disorder?

As autumn arrives, the number of daylight hours declines. The effect is greater the farther north a person travels from the equator. Daylight also can be decreased by cloud cover in specific areas of the United States, such as the Great Lakes region.

It is believed that for some people the decrease in available daylight causes a decline in the neurotransmitter* serotonin (ser-a-TO-nin), in the brain. A decrease in the amount of serotonin in the brain has been linked to depression, because serotonin typically is associated with feelings of well-being. In the autumn, after a few weeks of reduced serotonin levels, a person can start to show signs of depression. If left untreated, the depression may continue throughout the winter and then disappear in the spring as the number of daylight hours increases.

* neurotransmitter
(NUR-o-tranzmit-er) is a chemical messenger that lets brain cells communicate with each other and therefore allows the brain to function properly.

SAD is diagnosed in people if they become depressed in the fall and winter for two or more consecutive years, with periods of normal moods in the spring and summer, and if they have no other problems that might account for seasonal depression. A rare form of SAD, called summer SAD, occurs in reverse of the normal pattern. People with summer SAD become depressed during the summer and feel better in the winter.

What Are the Symptoms of SAD?

Not everyone who has SAD experiences all the same symptoms. Often people with SAD report feeling fatigue and oversleeping and a craving for carbohydrates, along with the tendency to gain a little weight. These symptoms occur along with other common symptoms of depression such as:

Winter depression is a common type of SAD that is caused by the dramatic decrease in sunlight when the seasons change. Patients who undergo light therapy may sit in a light box for about a half hour a day throughout the fall and winter, until springtime when there is more natural sunshine. Stock Boston

  • depressed mood
  • feelings of helplessness, hopelessness, or guilt
  • pessimistic thoughts
  • loss of pleasure in previously enjoyable activities
  • difficulty concentrating or making decisions.

How Is SAD Treated?

Once it has been diagnosed correctly, seasonal affective disorder can be treated with light therapy. People with SAD sit in front of special bright light boxes or wear light visors for a period of 30 minutes to 2 hours every day, glancing occasionally at the light. To be effective, the light must enter the eyes and not just fall on the skin. Occasionally, people report eyestrain or headaches from the light devices, but usually there are no negative side effects. When natural daylight increases, people with SAD discontinue light treatment.

See also

Depression

Resource

Organization

Depression and Related Affective Disorders Association (DRADA), Meyer 3-181, 600 North Wolfe Street, Baltimore, MD 21287-7381. A self-help and educational organization for people with depressive illnesses and their families. Telephone 410-955-4647 http://www.med.jhu.edu/drada

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seasonal affective disorder

seasonal affective disorder (SAD) Mental depression apparently linked to the seasonally changing amount of light. Sufferers experience depression during autumn and winter.

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"seasonal affective disorder." World Encyclopedia. . Encyclopedia.com. 23 Aug. 2017 <http://www.encyclopedia.com>.

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"seasonal affective disorder." World Encyclopedia. . Retrieved August 23, 2017 from Encyclopedia.com: http://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/seasonal-affective-disorder

seasonal affective disorder

seasonal affective disorder (see-zŏ-năl) n. see SAD.

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