(updated 10/2015)

(Don’t do this on your own. There are risks, described below. But these risks are almost certainly much smaller than those of medication approaches. )

Bottom line:  clearly more than a placebo. Dawn simulators are the first step (much easier to use, cheaper, no risk). If you are going to use a light box, read on.

How much light are you getting?

Light therapy can treat more than just winter depression, though that’s the main use. Here’s why: the amount of light reaching your eyeball from interior lighting is far less than the amount from the real thing. So unless you are outside much of the day in the winter, you are relying on electric light for your photons (in summer, there is so much light, most people get enough, even if they are indoors during their work hours). The following graph shows you just how much less light you receive, indoors versus outdoors (Lux is a standard unit of light flow):

Brightness Values:

Bright moonlight 1 lux
Candle light at 20 cm 10-15 lux
Street light 10-20 lux
Normal living room lighting 100 lux
Office fluorescent light 300-500 lux
Sunlight, 1 hour before sunset 1000 lux
Daylight, cloudy sky* 5000 lux
Daylight, clear sky 10,000-20.000 lux
Bright sunlight > 20,000-100,000 lux

Outdoors on a sunny day is 50-100 times brighter than office or room lighting.

*(depends on latitude: a northern winter day, far less than a southern or summer day, of course)

Okay, with that as an introduction, let’s look at light as a treatment for depression.

Start with a dawn simulator

Hold on a minute, before you go tearing off looking at light boxes (discussed below) . . . There is a far simpler way to do light therapy, which is even cheaper and so far has not been associated with hypomania or mania (which light boxes can cause).   It doesn’t work for everyone. But “treatment” is over by the time you wake up. No sitting for 30 minutes stuck in front of a light box.   If it doesn’t work, you might still like it (wouldn’t you rather wake up in room full of light than wake to an alarm and have to — whamo — turn on a bright light? ugh).

What is a “Dawn Simulator”? This is simply a device to gradually increase the light in your bedroom in the morning, while you are still asleep. Try this: close your eyes and look toward the light by which you’re reading this. You can tell where the light is, even with your eyes closed. A dawn simulator gradually turns on your bedside lamp in the morning, before you wake up, so that your retina (not you — you’re still asleep!) “sees” the light show up at the time you choose, increasing gradually just as natural sunlight does, over about 30-45 minutes. It’s really nothing more than a timer and a rheostat (a device to slowly change electrical current) hooked to your bedside lamp. Note that this approach does not require a “light box”.

Why is the gradual appearance of morning light potentially “antidepressant”? Think of it this way: the dawn simulator is trying to convince your brain that it’s still July out there (even in December). It turns out that your brain knows what season it is primarily by the time at which morning light appears (okay, it’s true, you can also tell the difference between snow, sleet, ice, freezing rain, and the warm summer sun; but evolutionarily, it looks like the brain’s timing was set by factors more closely associated with light.) We think that some people are built to slow down in the winter, something akin to hibernation. Think of a hibernating bear: sleepy, slow, hungry for carbohydrates, unhappy if awakened, grouchy, grrrh. Those symptoms are pretty close to the experience of “winter blues” for some people.

So, if those peoples’ brain could be tricked into thinking that it really isn’t winter after all, might that prevent this shift toward a kind of half-hibernating way of dealing with the world? It appears that for some people, this actually works.

In the following graph, the “negative ion generator” was low-dose, the placebo. (High-dose appears to be an antidepressant of sorts Flory).  Notice how the dawn simulator, while not as good as light box, is better than a placebo.Terman (down is getting better, these are depression scores over time from left to right)


Update 2015: dawn simulators appear to improve thinking ability in the morning, compared to waking and staying in dim light. Gabel2015, Gabel2013

So, to review:

  • it’s cheaper
  • it’s over by the time you wake up
  • you might like it even if it doesn’t work for mood
  • it doesn’t make bipolar disorder worse
  • it has no risks (except waking your partner)
  • and it might even make you think better!

Sold?  Here’s a page listing different versions by cost, and where to get them.

Now, on to light boxes — another way to do light therapy.

Light Boxes: Safety issues

A group of  experts maintains a website (CET.org) about all aspects of light therapy. Their discussion of safety issues is thorough; and maybe a little technical, so I’ll summarize here, but if you have any further need for information, that’s the place to go.

You need to learn more about light box safety before using one if (look up your medications or ask your pharmacist; ask your eye doc’;  or at least read the CET.org site’s page about risk) :

– you have macular degeneration

– family history of macular degeneration

– you have porphyria, lupus, actinic dermatitis (seriously sun-damaged skin), or solar urticaria (sun makes your skin hurt)

– you take a medication that sensitizes you to light

– “phenothiazines” (a kind of antipsychotic; check yours out if you take one)
–  some cardiac anti-arrhythmia med’s like amiodarone
–  treatments for psoriasis
–  antimalarials
–  St. John’s Wort
–  medications for rheumatoid diseases
–  and, lower risk but still worth checking out:
tetracycline, diuretics like hydrochlorthiazide, sulfa drugs, tricyclic antidepressants

And if you have diabetes and eye problems from that — well, you get the drift. This is high intensity light. You have to be careful with it.

Use Light Differently in Bipolar Disorder

If you already have figured out you have some degree of bipolarity (Bipolar II, soft bipolar disorder), then before you read on you should probably read about Bipolar Disorder: Light and Darkness.  Because there’s more to the story than light. Darkness might be even more important, especially if you’re having mixed state depression, because more light might be a bad idea at that point (it’s an antidepressant; antidepressants can induce manic-side symptoms; mixed states are combinations of depressive and manic-side symptoms; so light can induce mixed states, and make them worse. That was the short version).  Then come back here to learn more about light therapy, starting right here — because light therapy may need to be different in people with bipolar disorders.

If you don’t have bipolarity (someone who understands how to look for it has already helped you determine that), you can skip to the next section. Mind you, it is not easy to be certain about this. If you have any doubt, read more about bipolar II and more subtle forms of “bipolarity.”  You definitely should do this if you have someone in your family with a bipolar diagnosis.

Light Therapy in Bipolar Disorder

Light therapy is probably one of the safer antidepressant treatments for bipolar depression. Low “doses” can be safe for many people. But too big a dose can cause manic symptoms, just like any other antidepressant. So you have to be careful. Have your doctor help you find a safe dose — one which does not produce any “manic side” symptoms or interfere with sleep.

While you are at it, consider the following recent research finding. In a very small study, 6 out of 9 women with severe bipolar depression showed a clear response to light therapy.Sit They did not have “seasonal” depression, but rather bipolar depression (although the season of the year in which the data was collected was not reported, to my recollection ). Here’s the important finding: morning light may be more likely to trigger manic symptoms, leading to a “mixed state” of manic and depressed symptoms at the same time, than midday light. Interestingly, this almost exactly repeated the results of an earlier similar study, also with 9 women.Liebenluft

Following the usual protocol for life therapy, using it first thing in the morning (30 minutes before their usual wake time, in this case) three out of the first four women in this study developed mixed episodes (irritability, elevated energy, increased activity, creativity, aggression, racing thoughts, pressured speech). Based on that experience they changed the protocol so that everyone received light in the middle of the day instead. With this arrangement, four were full responders, meaning a complete or near-complete cessation of depression symptoms. Two others were “partial responders”, clearly improved but not fully.

Therefore, for the moment, the optimal timing of light therapy for people with bipolar depression is uncertain. For safety reasons it may be wise for people with bipolar depression to begin with midday light rather than morning light, switching to the morning if no improvement is seen. However, because this was such a small study, it is really too early to reach a firm conclusion on this. A standard approach to light therapy, using morning light, it is not unreasonable. One just has to watch out for the emergence of mixed symptoms as detailed above.

Update 2012: finally, a larger study of the use of light therapy in bipolar depression. Unfortunately, this study says “it doesn’t work”. Well, it helped, but not more than a placebo, in part because in this study the placebo response was huge.Dauphinais So what does this mean for use of light therapy for bipolar depression? Taken together with the 9-woman studies above, I’d say “well, it’s not a dud, but it doesn’t work very reliably in bipolar depression. I wouldn’t rule it out, but it’s not a very sure thing”. Remember, many people with bipolar disorder also have seasonal changes in mood, for which light therapy could be useful. But on the whole, one thing is clear: much safer –and cheaper and far simpler — is to start with a Dawn Simulator.

Light boxes beat placebos for depression

[updated 3/2016]

Not just for Seasonal Affective Disorder.  A recent head-to-head study of light vs. fluoxetine/Prozac (or the combination) showed light therapy to be better than a pill for Major Depression.

That’s a big leap. The details of the study are interesting. But the bottom line is that for someone who is prepared to try a light box instead of a pill, there’s a very good chance it will work well for depression!


If you’re not familiar with light therapy for seasonal depression, more information follows below. Basically one sits in front of a box the size of a small suitcase (smaller ones available; more on that below too) which emits a lot of light, for about 30 minutes to start, and as little as 15 minutes or less later to stay well through the winter.

The new Canadian research is one of several well-designed studies which when viewed together suggest that light therapy is an effective treatment for depression, roughly equal to medications in strength.Golden

So, if light therapy is that good, why isn’t it more widely recommended? For one thing, early research on light therapy was poorly funded and thus often of very weak design. Placebo comparison (“control” treatment) is hard to do. Think about it: how do you put someone on a “placebo” treatment that seems like light therapy but isn’t likely to do anything? It’s not like making an identical placebo pill. Researchers have used dim red light, mis-timed white light, and negative ion generator boxes as “plausible” placebo treatments. All of these control treatments have their problems.

Furthermore, as one of the leading researchers pointed out, everyone in the study is likely to get some additional light exposure just from seeing the sun once in a while. In Seattle, where Dr. Avery works, that might really be once in long while, in the winter! But if all patients in a research study are getting some sunlight during the day, at random times during the study, that ought to minimize the difference between the “treatment” group that is getting light box treatment, versus the “control” group that is getting something else. As Dr. Avery says, it’s as though you were trying to research on Prozac, with one group on the drug and one group getting placebo, but unknown to you, now and then someone was sneaking in and putting little doses of Prozac in the water supply of everyone in the study!

Because of these design problems, and the lack of a major industry to fund research on light treatments, early studies tended to be weak and contributed to the sense that light therapy itself is a weak treatment. And yet the two reports above (one a new study, one a good recent review of previous research) show that light therapy for seasonal mood shifts is not a weak treatment at all. And it may have similar strength even for non-seasonal depression. One study even found that hospital stays for depression were three days shorter for patients whose rooms faced east (thus getting regular morning sunlight), instead of west .Benedetti

Best of all, it is relatively cheap: the newest light boxes cost as little as $130-150 (a link in a moment). Compare the price of medications for a year, plus doctor visits to manage those medications. There are no medication interactions; and there are almost no side effects. Some people get headaches, some have some eye strain. But the main worry with light therapy is that it will work too much like a regular antidepressant: as with other effective antidepressant treatments, there are numerous reports of hypomania developing during light treatment. One of my patients got a speeding ticket after sitting in front of her box too long — twice!

Because of this risk, which includes mania Chan and even suicideHaffmans, you should not attempt light treatment on your own. This must be conducted with your physician as part of the treatment team, which includes planning for managing worsening during treatment. Do not do this on your own.

Basic Information About Using Light Therapy

If you need to start with some basics on light therapy, the Mayo Clinic site  will help you to learn about light boxes and how to use them.

Meanwhile, here is one of the most interesting research findings I’ve come across in a long time. People with seasonal mood changes have different responses to light in the winter, compared to summer — in their own retinas!Lavoie So whatever “Seasonal Affective Disorder” is, one thing is for sure: it has a biologic basis. (For more on the biologic basis of depression, see my essays on the Brain Chemistry of Depression).

Which Light Box Should I Buy?
(updated 10/2015)

You can choose from “certified” or “cheap”. You can also get yourself really confused by looking at “blue-only” lights. And if you read a lot about light box safety, you’ll get yourself pretty bewildered, I think.

Yet you are wanting to try one now, so you need some guidance now. Okay, for now, I think it boils down to getting either the official research-tested rig or the cheap one that in principle ought to work as well, if you use it properly (but that’s pretty unlikely).

A. The official research rig: Carex
Amazon:   this winter it’s $136 and free shipping (this used to cost $350 only a few years ago…)

Notice that the light box which comes with this stand is higher than her eyeball, and it’s LARGE, so if she moves her head a little the amount of light she sees will not change too much. That’s the crucial difference, comparing the next option.


B. The Cheap route
At $70 (Amazon) the Lightphoria is  a bit over half the price of the Amazon version of the Uplift.

LightphoriaBut even though they say it puts out 10,000 lux just like the Uplift, you’ll have to get this one about 6″ from your eye to obtain that intensity, whereas the Carex box above can yield that result at 12 inches. In either case, as you can see, they need to be close. You can also see that a small shift in the position of your head will reduce the light you get from this little one. If you must go this route, be careful to put something really interesting in front of you while using this treatment, so you won’t move around too much. The box does not need to be straight in front of you. The ideal position is shown in the Carex photo above.  It could also be in your field of vision but off to the side and up a little (e.g. on a pile of books very close to your head). You can address all these worries by spending another $70 on the big box, if you’ve got the cash.

C. What about the little blue guy?
Amazon $59. Product Details

a) too small, getting the field right would be really difficult
b) we bought some a few years back and they were, then, really cheaply made; the on/off switches didn’t hold up

What happened to the little blue light boxes?

As you may have read, blue light is wavelength that sets biological rhythms, including sleep/wake cycles in humans (here’s the Whole Story). So back around 2005, some companies started making little blue light boxes. They could be smaller because they were emitting just the “active ingredient” in white light. But now:

a) they’re not the cheapest anymore

b) there has controversy as to whether the little blue boxes are as effective as large white ones, although a new 2016 study suggests they are.Meesters

c) yet still, the big white boxes are much easier to use correctly (they’re set above your eyes, so no need for piles of books or some other placement; and they have a big field so you don’t have to look in one place for 30 minutes)

If you want to be really sure you have the same box that most of the research studies have used, you need the LARGE WHITE one above.

Mind you, there is a research study showing that a little blue box is better than a placebo.Glickman But one more debate gets hauled up about the blue boxes: Maybe they aren’t as safe as white ones — even though at least some of the white ones put out even more high-energy light (higher than blue) than the blue boxes.  All of these boxes have to be evaluated carefully for safety.

What do I recommend for my patients?  That’s much easier to answer as of 2014: go for the research-grade box. If it doesn’t work, sell it to your psychiatrist so that she has another demo to loan out (so that those who come after you won’t have to buy one to find out if it works).

*What about a visor approach?


If you have $200 to drop, not just $50, you might consider a green light visor, but only if you have to be walking around at the time you need the light therapy. If you can be sitting down at the needed time, the expense is not worth it, and the data supporting it not substantial enough (yet, anyway; as of 2013). You can’t easily read or use a computer, though it’s not impossible (my experience; versus an aviation study that panned the visor approach). You definitely cannot drive with this rig on.

Does the visor approach really work? The manufacturer offers four studies showing effectiveness versus control treatments. Unfortunately, none of the these has been published, near as I can tell ( Pub Med, 11/2014). That should be a red flag. Yet green light has been shown effective in other published work, using a light tower — much more expensive, not portable — instead of a light visor. So even though several large studies with white-light visors did not show benefit versus control treatment (Teicher; Rosenthal), we now know the active ingredient in all that light (blue or blue green; here is the whole story about blue light ). So theoretically the green visor might work, even if it does not have published evidence. Therefore you might consider it if you can’t sit for light therapy (e.g. busy parent in the morning?). You look kinda funny with this visor on your head, though: I got quite a few laughs wearing it around the hospital. So this may be a privacy-of-your-own-home thing.

I have to put the light box above my eyes?

Yes. The same team that developed the first blue light box also did an interesting experiment. They put a special helmet on patients undergoing light therapy, which allowed the light to hit only the top of their eyeballs, or the bottom. Why they thought this might be important, I don’t know — but they were right. It turns out you need use a light box positioned above your eyes, so that the light hits the bottom of your retina (like the top of the chicken below). Patients in the group with light hitting only the top of their retina (think chicken feet, which is what you’re doing with the light box down on your desktop) did not respond as well to the light therapy.Glickman


Think about it, this actually makes a lot of sense. Why would your body bother putting receptors for light at the top of your eyeball? The light you’re interested in is coming from the sky, not the ground, right? Evolutionarily they’d be much more useful at the bottom of the eye; why waste them at the top where they can’t “see” the light they’re supposed to be telling the brain about?

The point here: don’t put that light box on the tabletop next to your bowl of cereal and your newspaper. Put it up on something so that the light is coming down toward you (not very far away though: one foot for the research rig, and 6 inches for the little white box). I’ve been telling my patients for years to put their big suitcase-size light boxes on the table. Wrong.

What Time Should I Use It?

Light can be used for several purposes, including winter depression, which is one version of seasonal affective disorder — SAD, what an acronym. It can also be used for moving your sleep timing, even if you don’t have depression. Here we’ll focus on SAD.

For winter depressions , research has so far focused on using light therapy in the morning. Most studies have shown this to be more effective than evening light, when one timing is compared against the other and no further information is gathered about the patients participating.

However, things are getting more complicated now — which in this case is good. There may be a way to make the timing more personally tailored. Indeed, it appears that some people may do better to use light therapy in the evening. You see, exactly how light therapy actually treats depression has not been fully established. However, excellent research in this area has begun to suggest that light therapy works by re-setting your biological clock timing (your “circadian rhythms”) toward where it should be. For some people with SAD, their timing can be set to something closer to July rather than where their body seems to go in November through February!

This research uses language that can be difficult to understand (said I, using my own difficulties with it as a guide — maybe you’d find it easier to follow than I have). It speaks of the timing of sleep compared to when your melatonin begins to go up in the evening. To make things easier, though, Dr. Terman’s group has produced a system for telling you when to use your light box.

Their research suggests that light therapy may work best about 8-9 hours after one’s body starts secreting melatonin.Terman

This hormone is associated with sleep, and the time at which it stops being produced may be one of the most important signals to the rest of your body saying “it’s daytime now, time to get up!”. When is your melatonin onset? What time does your body start its sleep cycle? One way to tell, according to Dr. Terman’s group, is to use a questionnaire they developed to determine whether you’re a “lark” or an “owl” — a morning person or an evening person. I’ll bet you have some guesses!

They call it the Morningness-Eveningness Questionnaire (MEQ). Brace yourself: if you’re an owl, you might be able to start your morning light therapy as late as 8 or 9 am and see full benefit. But if you’re a lark, there is some evidence (not conclusive yet) that you should be starting your morning light treatment as early as 4 a.m.! Instead of trying to determine your hour of melatonin onset, and calculating 8-9 hours later as your light time, you can take the questionnaire. If it says you’re really a morning person, you may see more benefit from your light therapy by pushing the treatment time earlier, toward say 5 a.m. anyway.

The Morningness-Eveningness Questionnaire

This system is linked to a research process: your answers may benefit others.

Chronotherapy: an entire package of treatments for depression using light and sleep shifts

Chronotherapy puts light therapy together with sleep therapies to create a complete package treatment for depression that can replace or add to medication approaches. The
ingredients include:

  1. “wake therapy”
  2. “sleep phase advance”
  3. a light box
  4. a dawn simulator

You’ve already learned about light boxes and dawn simulators above. For more on the first two ingredients, see my page on Chronotherapy.

STOP HERE ! WARNING: excruciating details below . . .

White vs. Blue, and safety
Go read some other page; this is only for the really interested

This issue of eye safety cranked up recently with the arrival of the little blue light box. Back in 1992, a team of light researchers estimated that it would take 72 winters of daily 30-minute light therapy to reach the threshold for causing eye damage.Waxler But because the blue box puts out a wavelength that is theoretically more harmful than other wavelengths, there’s been a lot of interest in the safety issue lately. Ironically, the graphs below suggests that if anything, the blue box is safer than “full spectrum” or all-white units.

Output of energy by wavelength:  “full spectrum” boxes


From left to right on this graph are the colors of the visual spectrum of light (part of the larger “electromagnetic spectrum” which includes ultraviolet, which would be off this graph to the left; and infrared, which would be off this graph to the right).  Blue is between 450 and 500 nm (nanometers).

The black curve  is sunlight. The blue hump is the output from one of the little blue light boxes. The red and green curves are two different “full spectrum” light boxes.

Output of energy by wavelength:  Uplift unit (same as “research rig” above)


This is the research unit described above. Note the big spike at about 440 nm — same as the full spectrum boxes above.

As you can see, all the light boxes put out a lot less energy than summer sunlight (if you measured outdoor light in the winter in the northern part of the United States or Europe, that black curve would be much lower on the graph, in some places near or even below the output of the light boxes).

Notice that the blue box output (areas shaded in blue) has a relatively low peak, especially compared to sunlight. Second, note that the full-spectrum light box has two peaks below the blue hump and the Uplift has one big one. If there is any danger involved, then these blue peaks from the “white” boxes peaks are more dangerous to the retina for two reasons: first, these peaks are at a lower wavelength, meaning even higher energy; and secondly, they are larger (taller), meaning more energy as well. It’s a good thing that for the vast majority of people who might consider using a light box, the safety issues described above don’t apply.