Dark Therapy
(updated 8/2006)

[Update 2/2005: For at least 3 years this idea was based on two cases.  That's it, two cases.  Finally an Italian research team has studied the same approach in 32 patients, again finding it works.  You'll find the details from that study at the bottom of this page, and some links for much more information on the role of light and dark in bipolar treatment.]

This will take a little explaining, and then we'll come around to the treatment issue.  First, here's a story from the great research team at the National Institutes of Mental Health (NIMH), originally reported in Bipolar Network News from which the graphic below derives; later published by Wehr and colleagues.  

Here you see a 3 year record of sleep and mood for a man with rapid-cycling bipolar disorder.  How the NIMH managed to get these recordings I don't know.  On the left, marked by red, you see a sleep record (don't bother trying to figure out what it means, just look at the pattern, which will be obvious in a minute).  

Next to it, marked by purple, is the total amount of sleep per 24 hours (to the right is a lot, to the left is a little -- again, it's the pattern that matters). 

 On the right, marked by blue, you see a mood record that shows obvious and frequent cycling from manic peaks to depressive lows (the lows are slightly longer, you can see, especially the one marked ***).  

If you look closely you can see that the amount of sleep (under the purple arrow) closely matches the mood curve: less sleep during  +  peaks;  and more sleep during the depressive phases.  

The main point so far is to see the rapid and obvious cycling.  






Here is the same record, starting from the severe depressive episode marked before (***), and now continuing into treatment -- beginning at *.  Notice that almost as soon as treatment begins, his sleep becomes more organized (neat black and gray bands); his total sleep per 24 hours starts to be consistent *; and his mood curve starts to settle toward the middle *.  

So, what was this treatment?  NO MEDICATIONS.  That sounds great, doesn't it?  But it wasn't easy: the NIMH research team required this man to stay in darkness 14 hours every night, from 6 pm to 8 am the next morning.  (After a few weeks they eased up: only 10 hours of "enforced darkness").  

How could "darkness" treat rapid cycling? And what does this mean for your treatment?  





How does darkness treat rapid cycling? 

To understand this patient's response to this treatment, we must turn to our "biological clock".  For a stunning example of how powerful this clock is, and how important in bipolar disorder, have a look at an example of a patient who cycled every 24 hours, first a day up, then a day down -- and has matching laboratory evidence of cycling (hormones, even handwriting!)  The NIMH team theorized that in rapid cyclers, their clocks have lost the ability to respond to the timing of natural day and night

They knew that the a specific part of the hypothalamus, the suprachiasmatic nucleus (SCN), has direct nerve connections from the eyes.  It gets direct signals about how much light is out there.  And it has been shown to be the main location of the "biological clock" in many animals, including humans.  They thought that the SCN might get "desensitized" in some susceptible people by too much light, namely too much artificial light at night.  (For much more information on how light and darkness affect bipolar disorder through the biological clock, start with my page on Bipolar Disorder: Light and Darkness (2006), and try some of the links there as well -- cool stuff!)

They hoped that the could reverse this with its opposite -- enforced darkness at night.  They believed that the SCN could become more sensitive again, if given this treatment.  Perhaps then it would then have more influence over the body's cycling, as it is supposed to?  

They set out to test this idea by taking a person with rapid cycling, on no medications, and helping him get "plenty of dark".  In fact, they made sure that's what he got!  Every night he came to their research program and went into a room with a bed, but no lights.  He didn't have to sleep, but he couldn't do anything -- there was no light to read by, no television, no phone: "enforced bed rest and darkness".  You can see how well this worked for him from the curves above.  

What does this mean for your treatment? 

I hope the implications are obvious: you might be able to get by with less medication if you avoid late evening light and activity.  Unfortunately, because there is no pharmaceutical manufacturer selling "darkness", we don't have lots of funding to support research on this treatment.  So there have not been formal tests of this approach, except a second case report, and that Italian study, details below.

On the other hand, here's one treatment that has very few risks (the other is exercise, if you haven't read about that yet).  And it would be easy to move at least a little bit in the direction of less artificial light, and less late evening activity.  At worst, you'd spend some evenings lying there in the dark.  I know from my patients' reports that this is not trivial: it means lying there with your thoughts, which can be pretty rough.  However, look at this guy's curves again -- he did it, and look how fast things started changing for him (on no medications): 

I don't recommend that you try to treat yourself with darkness alone, that's not the point; rather, I suggest that you look at how much artificial light you're getting, particularly late at night, and try to cut back on that.  There is indirect evidence that blue light is the particular type of light you need to avoid at night (unfortunately, just like the kind of light your TV puts out). several manufacturers are making low-blue-light products which might be of use -- at least a low-blue nightlight, if not a filter for your TV! See more in the Bipolar Disorder: Light and Darkness essay. 

That Italian study of 32 patients used dark therapy (6 pm to 8 am) for only three nights, and still they were able to show that it was better than "treatment as usual".Barbini That's the good news. The bad news is that it only seemed to work if the patient had been in a manic phase for a relatively short period of time.  You see, the group of patients they studied did not have the "rapid cycling" pattern shown above, but rather a manic episode that was severe enough to require hospitalization.  On the other hand, one could interpret this as more good news, I suppose, in that dark therapy was able to help even the most extreme form of bipolar manic symptoms, and do it in three days!  Patients who received dark therapy required less medication and left the hospital earlier.  Note however that these patients were still getting the usual medication approaches, unlike the patient described above.  

With the addition of the Italian data, and since the risks of this treatment are minimal except for the utter boredom it surely inflicts, which I understand is not trivial, I think it's time to consider adding "dark therapy" for manic phases and rapid cycling.  At minimum we can presume, for now, that avoiding late nights in front of a TV or computer screen (or working graveyard shifts) is likely to help minimize the need for medication and possibly enable a speedier recovery.  If avoiding such light is impossible, learn about blue-light blocking (which has not yet been directly tested but follows the research in this area). 

Other relevant pages: