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Light Therapies For Depression
 (revised 3/2008)

(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. )

Warning: Safety Not Established (risk in macular degeneration?) 

As of 10/2006, the most recent publication on light therapy safety is from Dr. David Sliney, who is well known in this field. He concludes (this is a near quote, from a symposium in September 2006) that light sources show no potential for danger to the eye; that concern over use of the blue light box described below is not justified; and that a white light box like we used to use is not safer than the little blue one described below.  I think there may be more to this story, which I have included at the bottom of this page (the Whole Safety Story; including a reference for Dr. Sliney's statement). But for now, this is as official a statement about safety as one can find.  

In other words, at this point one of the most prominent experts on the safety of light therapy says it's safe. If someone else says different, the first thing to ask is whether they're likely to have a different point of view because of money -- will they profit from that different point of view?  If you're not satisfied with that summary, take the Whole Story link. 

Use Light Differently in Bipolar Disorder? Understand the Risk, Understand Your Diagnosis
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.  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 someone who understands how to look for it has already help you determine that you do not have bipolar disorder, 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".  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 from December 2007.  In a very small study, which we will need to see repeated before we take this finding too strictly, 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.  

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 life therapy, using morning light, it is not unreasonable. One just has to watch out for the emergence of mixed symptoms as detailed above.

Evidence

How about a head-to-head competition between light therapy and a typical antidepressant;  that would be one of the better ways to demonstrate that light really works to treat depression, wouldn't it? Just such a study was recently published:  about 100 patients in Canada, with depression in the winter, randomly assigned to either fluoxetine (formerly Prozac, now generic) or a standard light box.Lam

Here's what happened -- equal improvement in both groups, with light a slight bit faster in lowering depression scores (lower is better) at week one; fluoxetine in red, light therapy in blue; improvement is shown as a reduction in depression scores: 

How about that? Light therapy is as good as the standard antidepressant approach. With fewer side effects and much less overall risk (not zero risk, but less). 

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 now 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 Canadian research is one of the most recent 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.  And it appears to be very safe. There is no evidence of eye problems in regular users after 5 yearsGallin ; 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 suicide Haffmans, 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 Light Therapy 
There are plenty of sources you can go to on the 'net for this.  Read on down this page for more details about bipolar depression and light therapy, and about specific treatment options;  but if you need to start with some basics on light therapy, here is a site which will help you to: 

Dawn Simulators
Hold on a minute, before you go tearing off looking at light boxes (continued below).  There is a far simpler way to do light therapy, which is even cheaper and so far (literature search 9/2005) has not been associated with hypomania or mania, the primary risk with a light box.  And it's cheaper too.  It doesn't work for everyone who responds to a light box, but if it did work for you, it's clearly a better way to go. 

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 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 recent research review (Golden meta-analysis, above), dawn simulator treatment was found to have an effect of similar size to light box treatment in 5 studies. In other words, the dawn simulator seemed to have as much power to improve mood as a light box.  However, all of these studies were all from the same research group.  Although Dr. Avery's research group is one of the best in the business studying light therapies, it would be nice to see someone else able to get the same result.  Dr Avery is a passionate, kind man; maybe he and his team are so good at helping people believe a treatment is going to work, they could make  throwing Frisbees an effective treatment for depression.  If somehow they weren't so convincing when selling the control treatment, that could create this result all by itself. 

However, dawn simulators are cheap, and there is no evidence for doing harm.  So, if there is even pretty good evidence of effectiveness, this is worth considering.  Here's a separate page on dawn simulators for more details on models, where to find them, how to use them, and so forth.  

Which One Should I Buy?: The little blue light box
Light boxes used to be as big as suitcases. Now there's one that's about as big as your hand (with fingers extended). There's a great story behind this little light box, about NASA-funded research on a newly discovered light receptor in your eye that works when your eyes are closed.  On the basis of that research, I'm satisfied that this little box is as good as the old big ones. The bottom line: it's okay to buy this little blue one. It's cheaper, easier to use, more portable, less bright on your eyes in the morning, and several studies suggest (but don't absolutely confirm, yet) that it works as well as the old big ones. Here's the whole story about blue light; or you can piece this story together from the links on the manufacturer's website. It's the only light box I'm recommending to patients at this point. I have no connection to the manufacturer at any level (including no stock -- but you know, you might think about that...). They are available at Costco in 2006-7 for about $160. Here is the manufacturer's site, Apollo Health. If you live in Corvallis, OR, you can buy them at a good price locally; see below.  

[Update 1/2008: a reader just asked about another small box, the Litebook. Note that the LED's in this version are white, not blue. The manufacturers website does not indicate what kind of light or how much is coming out of their rig.  Without these specifications, or a randomized trial (such as was done with the Apollo unit above), I think the Apollo version is preferable at this point, and it even costs less.]

In research studies, boxes such as the SunRay from SunBox  have been used for years. They'll probably have to dramatically lower their price to compete with the little blue one (hasn't happened yet as of this writing in October 2006). So far there is no evidence that the little one works better; it's just more convenient to position and move around. 

What about other ones, a reader asks, mentioning for example the Full Spectrum Solutions products. I'm not an expert, but here's my sense of the difference. Although they will probably work as well as any of the older suit-case-sized light boxes, and theirs are more convenient in size and flexibility, the Full Spectrum products do not hit the most important wavelength of blue light, despite the name "BlueMax". The key wavelength, as described in that story about blue light, is around 465 nanometers. In the Full Spectrum products, according to their graph, there is a significant peak at a lower wavelength, and several peaks at higher (less blue) wavelengths, but only a small hump around 465 nm. Thus for a given amount of time in front of the light, the little blue one will work better, according to research available so far. The Full Spectrum products appear to be designed primarily for efficient reading and work area lighting, and for that, they may be particularly good if their explanation about pupil diameter is true. I have not investigated that claim. 

I have to put it above my eyes? 
Yes. The same team that developed that little blue light box also did an interesting experiment, which shows that I've been giving my patients bad advice about light therapy for years!  They put a special visor 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. Patients in the group with light hitting only the top of their retina did not respond as well to the light therapy.Glickman

Huh? Actually, think about it, this 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; only about 1-2 feet). I've been telling my patients for years to put their big suitcase-size light boxes on the table. Wrong. The little blue one ought to be easier to put up there somehow (I know, this is going to be a little challenging...).  

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. If you're up for it, here's a recent review by leaders in the field). It speaks of  the timing of sleep compared to when your melatonin begins to go up in the evening. To make things easier, though, two different research groups have produced systems for telling you when to use your light box. One group is well known in the field. We'll start with them but I think you'll want to look at the other group's online system as well; although it's not independently published yet, to my knowledge, their system accords well with everything I've learned so far about what light does to biological clocks. 

The first system is the work of Drs. Terman and colleagues in New York, whose research suggests that light therapy may work best about 8-9 hours after one's body starts secreting melatoninTerman.  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 the research of 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). I'll give you a link to their online version, at the Center for Environmental Therapeutics, at the bottom of this section. 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.  

However, an online test from another research team (Apollo Health) says it can tell you not only when to use the light but how to shift the timing, if necessary, as you get better. It's a much more sophisticated testing and reporting system. This system has not been published, to my knowledge. Indeed, it belongs to a company that makes a light box! That ought to make you really suspicious right there. However, in this case, having spoken with their research director, I think their system might be the place to start, at least for now. Theirs seems to be able to tell whether you might be one of the 20-30% of people who would do better to use a light box at night.  

This is tricky territory. I'm not an expert here (although lately it seems that I've been talking with quite a few folks who are!). Remember, the old way of thinking was just to use the light box in the morning, and that did indeed help a lot of people. But I think it may have missed some who could have benefited, if they had used the box at a different time. If you compare the two research groups' questionnaires, you may find that they are giving you different recommendations. I'm telling my patients that I don't know yet how to guide them if that happens. For now I'm suggesting to my patients to start with the first of the questionnaires linked below. The second system is linked just to make all the relevant resources available to you should you want them. 

A sophisticated online questionnaire: Apollo Health Systems
Warning: they're going to ask you for an email address before you get your results (which come right up on the next screen, you don't have to wait for an email reply). You have to put in a valid one (I tried to do otherwise, no go). 

The Morningness-Eveningness Questionnaire
This system is linked to a research process: your answers may benefit others. 

Light Box Sources and Prices

If you're lucky to live near Corvallis, Oregon....We're fortunate here to have a fellow who buys them in bulk and offers them at an extremely low price: as good as any I've found with some limited surfing, and with no shipping costs.  And, he'll buy them back  for full price if the box is in perfect condition -- so basically you can try it for 2 weeks and if it doesn't work, get your money back in full.  This is a great service, provided by:

Gentle Creations
Roger Brownell, owner
753 6346

For 2006 he'll have the little blue one described above, at the same price you'll find at Costco, $160 (Costco has the P2, with batteries as well as cord; Mr. Brownell has the P1, which is better in my view: no batteries to recycle).

If you don't live locally, though, you'll do about as well to pay the shipping to the company as to Roger, and he couldn't handle people from all over taking his deal (and besides, I want my patients to get those boxes!)

More resources

For more extensive information about light therapy in a question/answers format, see the FAQ from the Society for Light Treatment and Biological Rhythms.  Here's the best single overall reference article. 

The Whole Safety Story 
(Updated 7/ 2007) 

Light is good for mood, for some people, delivered in the right way.  That much is clear, as you've seen.  But a lot of light is also bad for some eyeballs, especially if it arrives in the form of blue light, because it can damage the retina in some susceptible individuals. Worse yet, it's not clear who's at risk for this damage, and who's not. However, the good news is that light boxes are less risky than the sun, it appears. (Update 2007: this issue is still under debate, although I cannot tell if the concerns which remain are motivated by concern for the public good, or by a desire for financial gain on the part of manufacturers of products which do not emit blue light. More on that in the 2007 update at the bottom of the page.)

In the following analysis, remember the bottom line from the simple version of this information that leads off this page:  one of the best known authorities on light boxes and their possible effects on the retina is on the record, as of September 2006, saying there is no evidence that they pose a risk.  

The problem with a lot of light, especially with blue light, is a condition called macular degeneration. The most common version of this condition, which appears to be related  to the amount of light hitting your retina over many years, is called "dry" macular degeneration.  Fortunately, this is a problem which takes years to develop. It also appears that not everyone is susceptible, but I haven't heard yet how one might tell if one was among those at risk.  Here's a good site with a lot of information about macular degeneration. 

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 damageWaxler  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 graph below suggests that if anything, the blue box is safer than the big "full spectrum" units. 

                 

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). The color band below the graph is supposed to be roughly positioned to match the wavelengths shown in the graph: for example, blue is between 450 and 500 nanometers. 

The black curve on the graph 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.  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 older light boxes have two peaks below the blue hump. If there is any danger involved, which is at this point not really an open question, at least according to one of the world's experts on the subject, then these two 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.  (A reader sent me a nifty trick: get a Chroma Green filter and put it over your old light box to create an output pretty close to the little blue box, just a little to the right, still at low enough wavelengths to get the desired effect on the circadian photoreceptor, presumably. He's testing that this winter. Thanks, HR). 

However, this graph comes from data gathered by the blue light manufacturer.  It would be nice to see an independent study. I've asked some light physicists to help me repeat this study and will post those results here when available. This issue is under study by several research groups including Dr. Charlotte Remé in Zurich, who has been very gracious in sending me information by email. Dr. David Sliney's statements at the very top of this page are found in the Proceedings of a symposium on Lighting and Health, held in Ottowa in 2006. Dr. Sliney was the featured speaker on this safety issue. The meeting abstracts are not online as of this writing (10/2006; Dr. Sliney kindly sent me a copy).

What about a green light approach? What if you just got pretty close to blue, close enough to stimulate the retinal receptors that are connected to the biological clock (explained in the story about why blue light is the one that matters)? Could you get the desired antidepressant effect with less risk (presuming there really is a risk; remember, that's not been established)? This is an approach being tried by another light box company; and of course they're making a great deal of noise about the risk of blue light, since that approach is what they are now competing against.  For example, there is one frightening story from the green-light company about one patient. When I sent this to Dr. Sliney, he reviewed the case again and points out that the retinal changes were in the very center of gaze ("macular"), which would imply that the patient was staring directly at the light box, were that to have been the cause.  Patients are generally instructed not to do this, and it would be physically difficult to do so long enough to cause this kind of damage.  More likely, in Dr. Sliney's view, is that this case represents damage from the sun, despite the suggestive timing, in part (my interpretation of his reply) because we know the sun can do this, whereas there is no clear evidence otherwise that light boxes can.  A bit circular, I grant you, if I've interpreted him correctly. At minimum we might conclude: don't look straight at your light box.  Read the newspaper or write your mother a letter.  (Revised 11/28/06)

More safety details, 2007

Murray Waldman, maker of the low-intensity green light box from Sunnex Biotechnologies, continues to send me information raising concern about blue light exposure and the risk of macular degeneration.  As of mid-2007, it still appears that the principal basis for this concern is the recognized correlation between the amount of sunlight exposure as a youth and young adult and the risk of macular degeneration many years later. I cannot tell whether his continued concerns about blue light risk are motivated primarily by his financial commitment to an alternative approach; nor likely could he, though he is very firm and forceful in his logic and his references to existing data.

As far as I can determine at this point, this correlation is the sole basis for claims that you will see by manufacturers of products which are competing with the "little blue light box" from Apollo Health Systems, which is the light box I am currently recommending to my patients (primarily because its cost is so low relative to other options; I have no financial connection to them).  For example, the NatureBright product using a white light advertises "no blue light which may cause vision problems such as macular degeneration". But the NatureBright light has not been directly tested in randomized trials, as best as I can determine from their website. It certainly has not been shown to be "twice as effective" as other light therapy products, which is such an overstatement that you might want to avoid using this product just to punish them for such misleading advertising (I believe the claim is based on some data suggesting that a combination of a dawn simulator and a light box is better than either alone; but this research did not use their product specifically). It still might be the best product, because it is now so cheap, and combines the light box and the dawn simulator, a very nifty feature -- and yet, we would want to see how much blue it puts out, and other wavelengths as well, just like the graph above, if we really believe that blue light exposure from these products presents a risk to the retina as one ages.