by Laurie B. Rosenblum, M.P.H.
Many people have difficulty dealing with the darker, shorter days of winter.
They struggle to get out of bed in the morning, have less energy, feel down, and
gain weight. For people with seasonal affective disorder (SAD), these changes
are severe enough to cause significant problems in their everyday lives. What is
SAD, how does it differ from the "winter blues" and normal sadness, and how can
it be treated?
What is seasonal affective disorder?
SAD is a type of depression that occurs due to a lack of exposure to light
during the winter. It begins in the fall (usually October or November) and
subsides in the spring (usually March or April). The onset and severity of the
symptoms are highly individualized and depend in part on where you live. The
number of cases and severity of symptoms increase with distance from the
equator. For example, people near the Arctic Circle tend to experience more
severe SAD starting earlier in the fall than people would while in the
Caribbean. A true SAD diagnosis can be made only after symptoms have lasted over
the past two winters for at least four weeks each time.
SAD symptoms can range from mild to severe. They may simply be a nuisance to
live with or severe enough to affect your ability to function. People who
experience symptoms too mild to be diagnosed with SAD but notable enough to be
bothered by them are often described as having the "winter blues," or "subsyndromal
SAD." Three to five percent of Americans have SAD and about another 10 percent
have subsyndromal SAD.
SAD occurs 3 - 4 times more often in women than in men. People of any racial or
ethnic group can be affected. SAD occurs most often during one's twenties
through forties, but children and older people can have it, too. Children are
more likely to be irritable instead of sad or anxious.
Common symptoms of seasonal affective disorder
The following symptoms typically begin in the fall, intensify in winter, and
subside in spring:
- Decreased energy and activity
- Tiredness, sleep more
- Sadness, anxiety
- Appetite changes (usually increased appetite)
- Carbohydrate craving
- Weight gain
- Loss of interest in sex
- Withdrawal from friends and family
- Difficulty concentrating and accomplishing tasks
- Premenstrual syndrome (worsens or only occurs in winter)
What is the difference between SAD, other types of depression, and normal sadness?
The main difference between SAD and other types of depression is that SAD
occurs only during the winter months. In many types of depression, people
generally eat and sleep less and lose weight; people with SAD usually eat and
sleep more and gain weight when it is cold and dark outside.
SAD, like other types of clinical depression, is not caused by psychological or
social factors, although such stresses can aggravate it. Normal sadness does not
generally include these physical symptoms, and is situational. The "holiday
blues" can be distinguished from SAD because they are generally not accompanied
by physical symptoms. They are caused by the typical stresses of the December
holiday season, and occur only around the holidays.
What causes SAD?
SAD appears to run in families. Most people with the disorder have at least
one close relative who has had bouts of depression (often SAD) at some time.
Lack of exposure to light seems to be the main trigger of SAD symptoms. However,
there are a variety of hypotheses as to the underlying biochemical process that
is affected by the lack of light.
An abnormality in one or more neurotransmitters and/or hormones is the suspected
cause of SAD. Neurotransmitters are the chemicals that carry messages between
nerve cells. The neurotransmitter serotonin is considered to be a likely cause
of SAD because its concentration in the brain varies with the seasons, the
smallest amount occurring during the winter.
Other chemicals under investigation include the neurotransmitters norepinephrine
and dopamine, and the hormone melatonin. The female sex hormones estrogen and
progesterone may also be involved, since women are more vulnerable to SAD than
men, especially in the years between puberty and menopause.
How can SAD be treated?
Light therapy
Light therapy is the primary treatment for SAD. It relieves symptoms in 75
percent of SAD patients within 2 - 14 days. Scientists believe that light
entering through the eye may modify brain chemistry, correcting the
abnormalities resulting from a lack of light.
Light therapy involves exposure under specified conditions to light that is 5 to
20 times brighter than regular indoor lighting. The person with SAD sits close
to a light box for 15 minutes to a few hours a day. Since looking directly at
the light is not recommended, usual activities such as reading, writing, and
eating can be carried out. The length of time and intensity of the light depend
on individual need and the equipment used. Initial evaluation and ongoing
supervision of treatment should be provided by a health care professional who
has experience with light therapy.
Although light therapy is safe for most people, it can cause eyestrain,
headaches, insomnia, and feelings of restlessness or irritability. These
problems can often be resolved by reducing the length of exposure or sitting
farther from the light box. People with certain types of eye disease or taking
medications that increase light sensitivity may not be able to use light therapy
or should use it only under closely monitored care from an ophthalmologist.
Lifestyle changes
Although light therapy is considered the first-line treatment for most people
with SAD, there are lifestyle changes you can try instead of or in conjunction
with light therapy. Some people experience improvement from increasing their
exposure to indoor light from regular lamps and to outdoor light by taking daily
walks during the morning or afternoon. Taking a winter vacation in a sunny place
with longer days may also help.
Getting regular aerobic exercise can also help improve mood in people with SAD.
Its effect is enhanced when done outdoors or in front of a light box. In
addition, exercise and diet can be used to control the weight gain common in
SAD. Since stress can exacerbate SAD, stress management is important, especially
during the winter months. Psychotherapy may be useful in coping with problems
that are causing stress.
Medications
Antidepressant medications can be used to treat SAD, but are usually prescribed
with light therapy instead of replacing it altogether. When light therapy is
only partially successful, medication may enhance the light's effect. Use of
light therapy in conjunction with medication may make it possible to take
smaller doses of medication and to reduce medication side effects. In addition,
taking medication reduces the time spent in front of lights.
The most frequently used antidepressant medications for SAD are the selective
serotonin reuptake inhibitors (SSRIs), such as Prozac, Zoloft, and Paxil.
Bupropion (Wellbutrin) and other antidepressants may also be effective.
What is the first step in treating SAD?
If you have mild SAD symptoms, start by increasing your exposure to regular
indoor and outdoor light. Try starting a walking program or a daily exercise
regime. If you have symptoms that are significantly interfering with your
quality of life, you should consult your health care provider and/or a mental
health professional. He or she can determine whether you do have SAD and discuss
available treatments. Remember, there are a number of different treatment
options that can be used alone or in combination that can help you feel better
and keep a brighter outlook on winter.
Further Reading
Anderson, Janis L. and Weiner, Gabrielle I., \"Seasonal Depression,\" Harvard
Health Letter: 21(4), page 7, February, 1996
National Institute of Mental Health, Clinical Psychobiology Branch, information
sheet on Seasonal Affective Disorder and light therapy. Bethesda, Maryland,
August 1996.
Rosenthal, Norman E., \"Diagnosis and Treatment of Seasonal Affective Disorder,\"
Journal of the American Medical Association: 270(22), 2717-2720, December 8,
1993.
Society for Light Treatment and Biological Rhythms, public information brochure,
\"Questions and Answers About Light Therapy.\" Wheat Ridge, Colora