reasonably well established that treatment with bright light is
effective for href="http://scienceblogs.com/clock/2007/07/seasonal_affective_disorder_th_1.php">seasonal
affective disorder (SAD). The standard treatment is
to have someone expose their face to 10,000 href="http://en.wikipedia.org/wiki/Lux">Lux
of bright light every morning, for 30 minutes, preferably at the same
time each day. Early studies indicated that it is the
not the color, that matters.
This is all very good, but bright light treatment sources are
necessarily big, fragile, and use a lot of electricity. The
are expensive, and they eventually burn out.
Subsequent research indicated that the timing of the light is
important. This implied that there is something about the
circadian rhythm that is related to seasonal depression. It
then learned that href="http://scienceblogs.com/clock/2006/08/wearing_blueblocking_eyeglasse.php">different
wavelengths of light have different effects on the circadian
rhythm in humans. Specifically, only blue light suppresses
the production of melatonin. It is the suppression of
melatonin that tells you it is time to get up and get going in the
All of this added up to something...
here, perhaps there is a more convenient way to administer
light treatment. All it would take is a light source that
only blue light, is more efficient than fluorescent bulbs, smaller,
that lasts longer.
That, of course, would be the LED (light emitting diode). The
open-source journal href="http://www.biomedcentral.com/bmcpsychiatry">BMC
Psychiatry has just published an update on this:
Controlled Trial of the Litebook Light-Emitting Diode (LED) Light
Therapy Device for Treatment of Seasonal Affective Disorder (SAD)
Paul H Desan ,
Weinstein , Erin E Michalak , Edwin M Tam , Ybe Meesters , Martine J
Ruiter , Edward Horn , John Telner , Hani Iskandar , Diane B Boivin and
Raymond W Lam
Recent research has emphasized that the human circadian rhythm system
is differentially sensitive to short wavelength light. Light treatment
devices using efficient light-emitting diodes (LEDs) whose output is
relatively concentrated in short wavelengths may enable a more
convenient effective therapy for Seasonal Affective Disorder (SAD).
The efficacy of a LED light therapy device in the treatment of SAD was
tested in a randomized, double-blind, placebo-controlled, multi-center
trial. Participants aged 18 to 65 with SAD (DSM-IV major depression
with seasonal pattern) were seen at Baseline and Randomization visits
separated by 1 week, and after 1, 2, 3 and 4 weeks of treatment.
Hamilton Depression Rating Scale scores (SIGH-SAD) were obtained at
each visit. Participants with SIGH-SAD of 20 or greater at Baseline and
Randomization visits were randomized to active or control treatment:
exposure to the Litebook LED treatment device (The Litebook Company
Ltd., Alberta, Canada) which delivers 1,350 lux white light (with
spectral emission peaks at 464 nm and 564 nm) at a distance of 20
inches or to an inactivated negative ion generator at a distance of 20
inches, for 30 minutes a day upon awakening and prior to 8 A.M.
Of the 26 participants randomized, 23 completed the trial. Mean group
SIGH-SAD scores did not differ significantly at randomization. At trial
end, the proportions of participants in remission (SIGH-SAD less than
9) were significantly greater (Fisher's exact test), and SIGH-SAD
scores, as percent individual score at randomization, were
significantly lower (t-test), with active treatment than with control,
both in an intent-to-treat analysis and an observed cases analysis. A
longitudinal repeated measures ANOVA analysis of SIGH-SAD scores also
indicated a significant interaction of time and treatment, showing
superiority of the Litebook over the placebo condition.
The results of this pilot study support the hypothesis that light
therapy with the Litebook is an effective treatment for SAD.
I would not necessarily endorse a product from any one vendor.
fact, the one mentioned in the article seems overpriced, in my opinion.
(Ultrabright blue LEDs can be gotten at specialty computer
and electronic shops, or eBay, for about 10 cents each.) I
should mention, though, that I don't recommend building these yourself.
There are blue LEDs that emit ultraviolet light, especially if fed too
high of a current. If you do not know exactly what you are
doing, you could end up making something that is not safe to shine in
This sort of research is interesting to me because it is very
practical. Potentially it could lead to a significantly less
expensive way to treat some mood disorders.
Thanks for the useful update on SAD treatments.
I've used a couple of the standard units--big, bulky, and too bright. If this proves out, it would be a nice affordable downsizing. Maybe even portable?
It is portable, comes with a lithium-ion battery good for two hours. It is about the size of a notebook computer.
No word yet on what the airline security screeners would think of it.
I use a 500 Watt quartz halogen lamp from Home Depot, $10. At 2-3 feet from it I measure ~10,000 lux. It is an incandescent source, so it is broad spectrum. I sit 3-4 feet in front of it while I eat my breakfast. Half an hour would be 250 watt hours, about $0.05 per day. The bulb lasts a couple of years.
I don't have diagnosed SAD, but I do feel better when I use the lamp than when I don't.
A quick read of the PDF doesn't reveal any attention paid to possible differences between younger and older participants. That is disappointing, as it's been suggested that blue light is less effective for older people for treatment of DSPS, and presumably also SAD.
I've used a couple of the standard units--big, bulky, and too bright. If this proves out, it would be a nice affordable downsizing. Maybe even portable? Thank You