What is Seasonal
Affective Disorder?
Many people
feel mildly "depressed" during the winter,
but some people have more severe bouts of feeling
down all the time, low energy, problems with sleep
and appetite, and reduced concentration to the
point where they have difficulty functioning at
work or in the home. Those people have a clinical
depression whereas Seasonal affective disorder,
or SAD, describes people who have these clinical
depressions only during the autumn and winter seasons.
During the spring and summer, they feel well.
Common symptoms of SAD include: extreme
fatigue and lack of energy, increased
need for sleep; sleeping much more than usual,
carbohydrate craving and increased appetite
and weight gain.
How common is SAD?
Researchers believe that SAD results from the shorter day length in winter.
Recent studies estimate that SAD is more common in northern countries because
the winter day gets shorter as you go farther north. In Florida, less than 1%
of the general population have SAD, while in Alaska as many as 10% of people
may suffer from winter depression. In B.C., 2% to 5% of people probably have
SAD. This means that up to 200,000 people in British Columbia may have difficulties
in the winter due to significant clinical depression.
What treatments are available for SAD?
An exciting new research finding is that many
patients with SAD improve with exposure to bright,
artificial light, called light therapy, or phototherapy.
In years past it took 1 –2 hours of light therapy to
be beneficial but now with the new
Blue-Lux™ Technology as little as 15 minutes is needed.
Using light therapy results in significant improvement
in 60% to 80% of SAD patients. Side effects of light
therapy are mild, although people with certain medical
conditions or taking certain medications should avoid
light therapy. Other treatments for depression, including
antidepressant medications and counseling, may also
be helpful for patients with SAD. People with milder
symptoms of the "winter
blahs" may be helped by simply
spending more time outdoors and exercising regularly
in the winter.
Why
does light therapy work?
Research shows that light has a biological
effect on brain hormones and function. One theory
is that people with SAD have a disturbance in the "biological
clock" in the brain that regulates hormones,
sleep and mood, so that this clock "runs slow" in
the winter. The bright light may help to "reset
the clock" and restore normal function. Other
theories are that changes in brain chemical (neurotransmitter)
function, particularly serotonin and dopa-mine,
may be disturbed in SAD, and that these neurotransmitter
imbalances are corrected by light therapy and/or
anti-depressant medications. Still other scientists
believe that patients with SAD have reduced retinal
light sensitivity in the winter that is corrected
by light
therapy. |
