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seasonal affective disorder
seasonal affective disordern. Abbr. SAD A mood disorder in which abnormal moods occur in a regular seasonal pattern, such as depression during the short days of winter. It is sometimes classified as a specific subtype of major depressive disorder or bipolar disorder.seasonal affective disorder n (Psychology) a state of depression sometimes experienced by people in winter, thought to be related to lack of sunlight. Abbreviation: SAD sea′sonal affec′tive disor′der
n. recurrent winter depression characterized by oversleeping, overeating, and irritability and relieved by the arrival of spring or by light therapy. Abbr.: SAD [1980–85] seasonal affective disorder(SAD) A condition resulting from changes in the body’s level of the hormone melatonin. The level varies seasonally: it is higher in winter and lower in summer, when increased daylight inhibits its production. Symptoms include tiredness and depression.Translationsseasonal 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 rhythm, biologicalrhythm, biological,
or biorhythm,
cyclic pattern of physiological changes or changes in activity in living organisms, most often synchronized with daily, monthly, or annual cyclical changes in the environment.
..... Click the link for more information. ). 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 glandpineal gland
, small organ (about the size of a pea) situated in the brain. Long considered vestigial in humans, the structure, which is also called the pineal body or the epiphysis, is present in most vertebrates.
..... Click the link for more information. , which is in turn controlled by an area (the suprachiasmatic nuclei) of the hypothalamushypothalamus
, an important supervisory center in the brain, rich in ganglia, nerve fibers, and synaptic connections. It is composed of several sections called nuclei, each of which controls a specific function.
..... Click the link for more information. ; 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. seasonal affective disorder[¦sēz·ēn·əl a¦fek·tiv dis′ȯrd·ər] (psychology) A syndrome of annually repeating depressive symptoms (usually overeating, oversleeping, and carbohydrate craving) that are related to changes in the season and are responsive to light therapy. Also known as winter depression. seasonal affective disorder
Seasonal Affective Disorder DefinitionSeasonal 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.DescriptionAlthough 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 symptomsThe 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.DiagnosisDoctors usually diagnose seasonal affective disorder based on the patient's description of symptoms, including the time of year they occur.TreatmentThe 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.PrognosisMost patients with seasonal affective disorder respond to light therapy and/or antidepressant drugs.ResourcesOrganizationsAmerican 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 termsCognitive 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.seasonal affective disorder (SAD) a mood disorder characterized by depression, extreme lethargy, increased need for sleep, overeating, and carbohydrate craving. It recurs each year in one or more specific seasons, most commonly the winter months, and is hypothesized to be related to melatonin levels.sea·son·al af·fec·tive dis·or·der (SAD), a depressive mood disorder that occurs at approximately the same time year after year and spontaneously remits at the same time each year. The most common type is winter depression and it is characterized by morning hypersomnia, low energy, increased appetite, weight gain, and a craving for carbohydrates, all of which remit in the spring.seasonal affective disordern. Abbr. SAD A mood disorder in which abnormal moods occur in a regular seasonal pattern, such as depression during the short days of winter. It is sometimes classified as a specific subtype of major depressive disorder or bipolar disorder.seasonal affective disorder A clinical form of depression with an onset in the late fall and remission in the spring; female:male ratio, 2:1.
Pathogenesis
Uncertain; reduced daily sunlight causes a drop in serotonin; PET scan data has linked depression to an increased in blood flow through the anterior limbic system, which may ultimately lead to hypoactivity; melatonin is decreased in women in summer and unchanged in men.
Management
Some SAD patients respond to high-intensity light, which alters the circadian rhythm, a therapy that is most effective in the morning; a light intensity of 10,000 lux viewed at close range may reset the biological clock.seasonal affective disorder SAD, winter 'blues,' winter depression Psychiatry A clinical form of depression with an onset in late fall and remission in spring. See Bright light therapy; Cf Melancholia, Melanocholy. sea·son·al af·fec·tive dis·or·der (SAD) (sēzŏn-ăl a-fektiv dis-ōrdĕr) A depressive mood disorder that occurs at approximately the same time year after year and spontaneously remits at the same time each year. The most common type is winter depression, characterized by morning hypersomnia, low energy, increased appetite, weight gain, and carbohydrate craving, all of which remit in the spring. sea·son·al af·fec·tive dis·or·der(SAD) (sēzŏn-ăl a-fektiv dis-ōrdĕr) Depressive mood disorder that occurs at approximately the same time each year and spontaneously remits at the same time each year. Most common type is winter depression characterized by morning hypersomnia, low energy, increased appetite, weight gain, and a craving for carbohydrates, all of which findings remit in the spring. LegalSeedisorderAcronymsSeeseizure-alert dogThesaurusSeesad |