February 19, 2004
Why so SAD?
Do you feel blue when the
days get shorter? During the winter, do you experience a greater
need for sleep or notice an increase in your appetite? Do these
symptoms lessen in the spring only to reappear in winter? If you
answered yes to any of these questions, you may be one of the millions
of people with seasonal affective disorder (SAD).
The key to knowing whether these symptoms can be
attributed to SAD or another cause of depression is whether your
symptoms appear during the winter and disappear in the spring. Of
course these are generalities, so I recommend you seek the advice
of a health care professional if your symptoms persist or are debilitating.
The most common symptoms of seasonal affective disorder are:
What is Seasonal Affective Disorder?
The short, dark days of winter limit your exposure
to the natural outdoor light from the sun that regulates your biorhythms
of waking and sleeping. In recent years, studies have confirmed
that sunlight enhances the function of the adrenal glands, which
helps your body deal with stress. It also plays an important role
in bone health, because it stimulates the body’s production of vitamin
D. It is not surprising that women who are sensitive to the seasonal
change of light report symptoms of mild depression.
Studies indicate that several of the brain’s neurotransmitters,
including melatonin, serotonin and dopamine, are lower in women
experiencing SAD. But, the real culprit seems to be the amount of
light coming through your eyes! This makes sense because light receptor
cells in the retina transmit information to cells in the hypothalamus,
the “master gland” of the brain. The hypothalamus sends
out messages that help to regulate mood, appetite and menstrual
cycles, and even some that affect the quality of your sleep. For
example, when you are light-deprived, the hypothalamus relays messages
to the pineal gland to release more melatonin, which can make you
feel more sleepy.
A little bit of light makes a big difference
I have found that adequate exposure to the right
kind of light may be all you need to improve your symptoms. All
that is required is an extra hour of sunlight per day. Some of my
patients have even experienced relief after replacing standard light
bulbs with those that approximate sunlight. These little beacons
can be found in most home center stores.
If you don’t have the luxury of being able to spend
an hour in the sun every day, there is another great way to get
the light you need. In 1984, Norman Rosenthal, a psychiatrist at
National Institute of Mental Health, published a paper on the use
of bright light therapy in patients with this disorder. Bright light
therapy uses specially designed light boxes that are equipped with
fluorescent bulbs, a metal reflector, and a protective plastic screen.
(They look like a miniature version of the devices that illuminate
stadiums during night games.)
The typical light box provides 10,000 lux of bright
indoor lighting, which is still only one tenth of the intensity
of sunshine. In most instances, a box is positioned one to three
feet away from the user, who is free to read, work or exercise.
Generally, I’ve found that 30 minutes of exposure each day, preferably
in the morning, is all that you need to improve your mood and reduce
Another light device, the dawn simulator, has also
been found to be effective in treating SAD. The simulator gradually
increases morning light exposure by turning on an indoor light before
sunrise, in essence making the sun come up earlier in the day.
Do not confuse light boxes with tanning lamps.
The critical factor in causing and relieving SAD is the amount of
light your eyes receive. Tanning lamps expose the skin, not the
eyes, to light. Plus, tanning lamps are designed to deliver large
doses of skin-damaging UV rays, whereas the lights used to treat
SAD downplay this harmful portion of the light spectrum. Side effects
from light therapy are rare, and most often include jitteriness,
a feeling of eyestrain or headache.
Other ways to “lighten up”
Although SAD accounts for many cases of winter
depression, it isn’t the only cause. Other potential triggers may
be responsible, for example being “cooped up” and isolated,
getting more exposure than usual to indoor allergens that you may
be sensitive to, and facing emotional issues linked to the holidays.
If a few weeks of light therapy doesn’t alleviate
your depression, you should explore some stress reduction options,
such as exercise (especially outdoor exercise), yoga, or meditation.
St. John’s wort, an herbal remedy, has also been used to successfully
treat patients with SAD. A word of caution: St. John’s wort can
negatively interact with other antidepressants and melatonin. It
can also increase your sensitivity to the sun, so if you plan to
spend time in the sun while taking St. John’s wort, take extra care
to apply sunscreen and avoid being in the sun from 10:00 a.m. until
2:00 p.m. when the sun’s rays are strongest.
Read More on Depression:
in Your Diet