Got a blue theraputic light last year. I waited til mid-winter, where by that time my effective “awake” time was about 4 hours a day. I dragged around for another 4 or 6 hours, and slept for enormous amounts of time.
In less than a week of use I got several more hours of effective awake time. The difference was really amazing.
I haven’t noticed a difference in mood, other than not feeling sluggish and unfocused all the time from being so tired. SAD pretty much just mangles my sleep patterns rather than affecting my mood.
The research I did on light boxes came mostly from the Mayo Clinic:
http://www.mayoclinic.com/health/light-therapy/MY00195
This checklist was great (the meat is on page 2):
Unfortunately, the other source I found re-arranged their website so I can no longer find the medical study overviews they used to have. But the gist was:
Full-spectrum lightboxes (white light) need to be at a minimum 10,000 lux in intensity to be considered theraputic. This is especially important if you plan to file a claim with your medical insurance.
Blue spectrum light (as long as it’s specifically designed for SAD symptoms) is more effective at lower intensities. You do not need the full 10K lux if you have a theraputic blue light.
Light therapy is affective through the eyes, not the skin. You need your eyes open to gain the most benefit (although I suppose light leak through your eyelids might help a little).
The receptors that respond to the theraputic blue wavelengths are on the periphery of your vision, so the light should be at a slight angle to your face and you shouldn’t look directly at it, although it should be within your field of view.
Here’s a couple executive summaries of the blue light studies, if you can wade through the included sales pitch:
http://www.lighttherapycanada.biz/bluelightresearch.htm
I got mine from http://lighttherapy.com/ – which was also the place that used to have an entire section of their website devoted to the medical studies, but no longer, which annoys me. In any case, I got the GoLite Blu, and I like it a lot. Still using it this year, though I’m having more issues with delayed Circadian rhythms this year, too. I can’t imagine how rough it would be if I weren’t using the light.
It cost just shy of $300, and my health insurance company has finally admitted that they cover high-intensity light boxes, but it’s a year later and they still insist that I have a UV dermatology light and are refusing to pay (don’t ask me where they got the idea that it’s a UV light, it’s never been on any of the paperwork I submitted, and suspect they are just making shit up to avoid paying the claim… just to let you know what you might be in for).