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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 SAD.
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, 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. 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 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activities (including sex), become withdrawn, crave carbohydrates, and gain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
(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, and 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 months 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 focus on the table it sits upon, 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).
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.
Gale Encyclopedia of
Alternative Medicine. Gale Group, 2001.
Expected results
Most patients with seasonal affective disorder respond to light therapy 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 sleeping more will increase natural melatonin.
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