How is SAD similar to other
"Affective Disorder" is
a broad term for the various forms
of mood disturbances from which many
people suffer. In particular, a major
depression may affect as many as 20%
of the American population at any
A major depression, seasonal or otherwise,
is characterized by a series of symptoms:
Symptoms of S.A.D. may include the
* Change in appetite or weight
* Sleep problems
* Lack of energy
* Diminishing sex drive
* Body aches or pains
* Memory loss
* Inability to make decisions
* Problems concentrating
* Low self-esteem (feelings of worthlessness
* Lack of interest in or enjoyment
* Suicidal thoughts
How is SAD different from other
As in the case of major depression,
the diagnosis of SAD is a clinical
one, based on the presence of specific
symptoms. To meet the criteria for
a seasonal relationship, there should
be at least three episodes of mood
disturbance in three separate seasons,
at least two of which are consecutive.
There should be no association between
the disturbance and situation stresses,
such as being unemployed each winter.
How can S.A.D. be treated?
In many ways, the treatment of SAD
is similar to that of other major
depressive episodes, utilizing antidepressant
or mood stabilizing medication and/or
psychotherapy. In addition, the exposure
to bright light has been found to
be an effective means of treating
seasonal affective disorder. The individual
sits in front of a bright light unit,
a specialized, portable box which
houses balanced spectrum fluorescent
tubes. An individual's needs for light
therapy specifies the duration of
exposure and the optimal time of day.
An individual should meet periodically
with their health care professional
and the dose of light therapy can
be adjusted as needed.
How the light box works:
The light box provides a measured
amount of balanced spectrum light
equivalent to standing outdoors on
a clear spring day. This has been
shown to help regulate the body clock.
Photobiologists point out that the
light is registered by the eyes through
the retina, which then transfers impulses
to the hypothalamus in the brain to
normalize the body clock function.
The light from the box will help synchronize
sleep/wake patterns with ones work
and life style.
Who Suffers From S.A.D.
About 3/4 of S.A.D. sufferers are
women, but S.A.D. affects men and
children as well. The most typical
age of onset is in the twenties, but
other onsets are common such as during
puberty, middle age, and old age.
After women pass through menopause
the numbers in men and women become
equal. Susceptibility for S.A.D appears
to be inherited. Fifty percent of
fibromyalgia patients see a seasonal
worsening of their symptoms.
Factors Influencing Severity
S.A.D. can be experienced as an isolated
disorder or may be experienced in
conjunction with an existing mood
disorder or chronic illness. The tendency
toward S.A.D. or severity of the symptoms
can be influenced by many factors,
such as living in a northern latitude,
recent cloudy weather patterns, family
history of S.A.D., working in a windowless
office, recent illness, or general
What causes S.A.D.
Change in sunlight exposure is the
key. The amount of day light exposure
one receives and the changes in sunrise/sunset
reducing the daylight hours in the
fall and winter can affect suffers
of S.A.D. The most commonly believed
hypothesis follows: although the body
has natural daily rhythms, they are
not fully precise and rely on the
intensity of sunlight to provide adjusting
cues. These cues originate in the
retina at the back of the eye, creating
signals which pass through the optic
nerve to the mid brain, setting in
motion a number of chemical changes.
These changes include:
1) Increase in the neurotransmitter
serotonin, necessary for a sense of
2) Regulation and suppression of the
hormone melatonin, which is a factor
in normal sleep patterns and may influence
sleeps recuperative benefits.
Basics of Bright Light Therapy
The most common device used for bright
light therapy is a fluorescent light
box which produces a light intensity
of 2,500 to 10,000 lux at a comfortable
distance (1-2'). Light box intensity
ratings are always at a given distance.
Light weight portable boxes and those
mounted on a stand are available.
Full-spectrum light is not necessary
since intensity is most important,
but a balanced-spectrum light minus
UV-B emissions is considered ideal.
Fewer headaches and eyestrain are
associated with using balanced spectrum
light. Most light boxes cost from
$250 to $525. Light visors which use
a battery pack, are worn on the head
and allow for mobility. Light Visors
appear to be at least as effective
as light boxes because the light source
is close to the eyes. Dawn/dusk simulators
are rheostat timers which are used
in conjunction with a bedside lamp.
These units gradually turn on the
lamp light over a preset or variable
period of time. Dawn/dusk simulators
appear to be most effective for those
with mild symptoms, for those who
did not succeed with bright light
therapy, and for those who have success
with bright light therapy but still
have difficulty waking up.
How Light Boxes Are Used
The light box is placed in front of
the user at the recommended distance
for the desired intensity. One should
be directly in front of the unit as
the light shines into the users eyes.
The eyes need be open, and sunglasses
should not be worn. Some may be instructed
to look at the light box briefly at
regular intervals. For many this doesn't
seem to be necessary. The light box
intensity of 10,000 lux is much brighter
than normal indoor light which is
usually 300-500 lux, but not as bright
as summer sunlight which can be as
bright as 100,000 lux.
How often do the Light Box
lamps need to be replaced?
It is recommended the lamps be replaced
after 2-3 years. the lamps do not
burn out but lose their intensity.
If you find that it takes you longer
to feel the same compared to when
your light box was new, it may be
time to replace your lamps in the
Exposure time is determined by the
intensity of the light source . There
are individual differences, but a
1/2 hour treatment at 10,000 lux or
a 1 hour session at 5,000 lux once
a day is the average. Most are comfortable
with the 10,000 lux intensity level,
and choose a unit that produces 10,000
lux at a usable and comfortable 13-16"
distance from the light box. If eyestrain
occurs it may be necessary to have
shorter periodic sessions.
Bright Light Therapy Timing
The most successful treatments for
S.A.D. involve identifying how the
change in daylight shifts the person's
daily circadian rhythms, especially
in their sleep cycle. Most with S.A.D.
symptoms show changes in their sleep/wake
patterns and melatonin levels. Bright
light is known to be a powerful regulator
of melatonin and the sleep/wake cycle.
S.A.D. and "Winter Blues"
sufferers tend to show two common
patterns in their sleep phase: Delayed
Session Timing for "Phase
About 80% show this pattern, this
groups melatonin production and sleep
period begin later at night, and moves
into the normal morning waking hours.
These patients have trouble waking
up in the morning, and often feel
sluggish for hours after awakening,
even if they have slept longer than
usual. Phototherapy sessions appear
to be most effective for this group
if placed between 6-8 a.m. Some experience
a time during late afternoon or early
evening that they become tired. Of
those in the phase-delayed group about
50% have this tired time. Late evening
arrives and the energy levels increase,
which makes going to bed at a normal
time difficult. This may also result
in poor sleep quality. For those,
an optional second session of 5 to10
minutes at 10,000 lux between 3-7
p.m. helps change this pattern and
often improves sleep quality. This
additional light may cause some users
difficulty going to sleep.
Session Timing for "Phase
About 20% of this group feel best
in the morning, then around noon their
energy levels steadily decline. Often
they retire for the night hours earlier
than normal. Their 30 minute session
at 10,000 lux is usually placed from
3-7 p.m., depending on when the urge
to sleep occurs and how late the light
may be used without keeping them awake.
Timing is more individual for this
group, and may require trial and error
for optimum effect. Short, periodic
sessions throughout the afternoon
at high intensity, or long exposure
at a lower intensity may also be considered.
A second session in the morning is
often not beneficial for this group.
Beginning and Ending Bright
Regular daily usage at the same time
each day is best until symptoms disappear.
After that period the patient may
be able to cut session time or split
a half-hour AM session into 15 minutes
a.m. and p.m. Once established, most
can skip a couple of days without
ill-effects, but by the third day
without light therapy most will see
symptoms return. Light therapy sessions
should begin at the time of the year
before symptoms become obvious or
distressing, and most patients will
discontinue use in the spring when
they receive enough natural light.
The times when usage is necessary
can be greatly affected by the amount
of sunlight or cloudy rainy weather.
It is possible to overuse a light
box. After overuse for 4 - 6 weeks,
irritability and agitation which is
often followed by fatigue may result.
Irritability, agitation and initial
eyestrain for 1-3 days appear to be
the main side effects. Inducing mania
is seen in about 1% and any mild hypo-mania
that may occur results from consistent
overuse. Some drugs make patients
photosensitive, as can contact lenses,
and those patients may need to be
conservative when starting light therapy.
Those on antidepressants can often
reduce their dosage, with their doctors
consent, once light therapy works.
For most patients, light therapy is
the most natural and safe treatment
for S.A.D., as well as the most cost-effective.
Given the effectiveness of treatments
for S.A.D. it would be a shame for
anyone not to seek help. It is true
that S.A.D. is often correctly self-diagnosed
and anyone can purchase light devices,
but other illness factors may be at
play, and seeking the guidance of
a qualified medical practitioner in
both the diagnosis and treatment of
S.A.D. is the wisest thing to do.
(Usage patterns outlined herein represent
those most typically given by current
clinical practices. They are not intended
to encourage self-prescription or
to contradict an individual's prescribed
* Always refer to instructions for