A Cheaper SAD Lighting Solution

I originally wrote this web page back around 1996. I haven't had a significant depression for several years now, so I'm not still using the lights for SAD, but I'll leave the information up in case it comes in handy for others.

This page is about my own solution to producing bright light for the treatment of Seasonal Affective Disorder (SAD). I'm not going to try to summarize what is known about SAD or about the use of bright lights to treat SAD.

Instead, my goal here is to describe a relatively inexpensive way to produce bright light which I believe to meet the usual clinical recommendations for the treatment of SAD. If you're comfortable using a drill and a screwdriver, you should have no problem following the same solution if you choose.

After I was diagnosed in 1996 by a psychologist as having SAD, I read up on SAD and decided to try light therapy. When I looked into commercial light boxes, I was put off by their price; depending on features, the prices were generally around $500 or higher. Further, most light boxes use fluorescent light, and I have a personal dislike for fluorescent lighting. I decided to improvise some less expensive solution.

Type of bulb

The literature on light therapy generally recommends a brightness of 10,000 lux as treatment for SAD. This is much brighter than ordinary interior lighting, but is still not nearly as bright as sunlight. One could achieve 10,000 lux by using a great many ordinary incandescent bulbs, but this would be a waste since much brighter bulbs are available relatively inexpensively.

There is some debate over whether full-spectrum light is necessary in light therapy. Full-spectrum light is light which emphasizes all of the colors in the visible spectrum equally strongly; if you pass full-spectrum light thru a prism, all of the colors of the resulting rainbow will be equally bright. Sunlight is the best known example of full-spectrum light.

By contrast, many artificial sources of light emphasize certain parts of the spectrum; for example, most fluorescent light strongly emphasizes blue-green portions of the spectrum.

Note that spectrum is not the same as brightness. Even though the fluorescent light emphasizes only certain frequencies, it can still be as bright as a full-spectrum light. The energy in full-spectrum light is simply dispersed over broader ranges of the visible frequencies.

Some light therapy products are non-full-spectrum; most are fluorescent, and at least one vendor sells a SAD treatment product which emits a bright red light. A reader has brought to my attention two articles which report no difference in the efficacy of full-spectrum and non-full-spectrum light; I haven't read the articles myself, however (the partial citations as the reader sent them to me are "rosenthal winter blues isbn 0-89862-149-6 and sltbr abstarcts june 1989 (and possibly republished somewhere else, try websciences.org search engine) Lebegue B, Brown JL"). Since I was able to find full-spectrum bulbs at a suitable price, I decided to go ahead and buy them, even though a non-full-spectrum type of bulb might have served just as well.

The type of bulb I decided to use is a tungsten-halogen bulb manufactured marketed under the name SoLux (I do not have any affiliation with the vendor of this product). The vendor's literature states that the bulb provides a very even full-spectrum light, but emits much less ultraviolet and infrared light than other tungsten-halogen bulbs.

Update, November 1998: I haven't checked the market recently to see what competition SoLux might have. If anyone knows of comparable products which I should discuss here, please let me know.

The SoLux bulbs are offered in three styles: narrow, medium, and wide beam (12°, 24°, and 38°). The wider the beam, the less bright the light on any given spot, since the total light is more spread out. I ended up choosing the medium-beam bulb. The vendor's literature states that one medium-beam bulb provides 9,588 lux at a distance of .6 meters, and 2,397 lux at a distance of 1.2 meters; since I planned to mount three lights about a meter from where I usually have my head positioned, the total brightness should be roughly 10,000 lux (the total lux is computed by summing the lux of the individual bulbs).

I bought a total of 7 bulbs (3 for each of two locations, plus one spare); the total charge to my credit card was US $109.65. I bought the bulbs in 1996, and as of the most recent update to this page (November 1998), none of them have burned out.

Track-lighting hardware

After I picked out the type of bulb, I went to Home Depot (a large hardware/lumber chain) to make sure that they had hardware for the MR16-type halogen bulb. There were indeed several hardware choices for this type of bulb. There was also hardware for bulb types other than MR16, so if you choose some kind of bulb other than SoLux, you will probably be able to find suitable hardware (I would confirm this before ordering the bulbs, though).

Since MR16 bulbs take 12 volts, you need a step-down transformer from household current, which is 120 volts. All the track lighting fixtures I saw had a built-in transformer inside the fixture, so this is a detail you don't need to worry much about.

You can buy tracks and track light fixtures separately, but the hardware I chose included the tracks and the fixtures in a single package. The tracks are intended to be wired directly into the house wiring, but you can buy an adaptor which allows you to plug the track into a wall socket instead:

Altogether, I paid $123.31 for these two sets of hardware, including the wall socket adaptors and Pennsylvania state sales tax. Thus, the total cost for hardware and bulbs was $232.96, which is about half the cost of a typical commercial light box.

I mounted one set of lights over my bed and another set over my computer desk. I turn on the lights over my bed first thing on dark winter mornings in hope of tricking my body into thinking that the sun is up. I mounted the other set over the computer since I usually work there for several hours a day.

One concern I had was that the bright lights would cause a glare on my computer screen, and I planned to buy an anti-glare shield. Once I had the lights installed, though, I didn't find glare to be a noticeable problem.

Some drawbacks to this solution:

When I first installed the lights, I would get a hot smell when I turned them on. This smell has gone away over time, but it made me paranoid about the possibility of fire.
At least one of the transformers makes a faint buzzing sound, which I find mildly annoying.
I don't have the equipment to test how much electromagnetic radiation the transformers are emitting, but it's possible that having three transformers so close to me might be dosing me with unsafe levels of EM radiation. (I have the same concern about my computer, etc.)
The bulbs were a little too big for the fixtures (or else the fixtures were a little too small, depending on your view). I had to leave out the little glass cover that goes over the bulb to get the bulb to fit inside. (After reading this page, the manufacturer of the SoLux bulbs wrote and told me that the glass covers probably aren't necessary anyway, since the bulbs "come with cover glass already incorporated into the bulb").
A reseller of SoLux bulbs has written to me and warned me that the surface of the bulbs is bright enough that you should avoid looking directly at the bulbs. Some SAD lighting products come with a diffusion shield to solve this problem.

Results

Did the lights help me this last winter? I am tempted to say yes; I experienced far less depression this winter than the one before, when I was not using lights. My tentative conclusion is that the lights were at least partially responsible for this. Of course, my one personal experience isn't enough to support this conclusion. It also happened that I was also under less work stress this last year than the year before, so it's not really a fair test to compare the two; and of course there might have been a placebo effect, etc.

Still, this solution is comparatively inexpensive enough that I'd recommend that others give it a try. At least on paper, it works out that I'm getting as much light this way as if I had bought a $500 light box, but I only spent around $230 on bulbs and track lighting hardware; so to the extent that bright lights are an effective treatment for SAD, this ought to work as well as a light box.

Update, November 1998: I'm now going into my third winter using this lighting arrangement. I can still only give you my own anecdotal experience, but I can safely say that I've experienced far less winter depression since I started using the lights. It's finally gotten so that I don't dread the coming of winter. Normal caveats about the placebo effect, etc., apply.

For the sake of completeness, I include some emails here concerning a discussion about possible hazards of light therapy. I looked into the matter some, and I feel confident that light therapy is not dangerous (assuming you don't do something silly like stare right into a bright bulb), but I've included the information here so that you can make your own informed decision.