Cloudy thinking on light therapy

The winter blues are commonplace (allegedly). Most of us in Northern climes have dull days when we’d like to float a little longer in the dreamy cloud of a warm duvet rather than tackle the cold, hard-edges of cloud computing and the day job. Limited exposure to sunlight and the feelings of lethargy it brings have even been medicalized in the form of Seasonal Affective Disorder, SAD, a rather too convenient acronym, to my mind. However, there are studies that show that the so-called “winter blues” are actually more common in summer or moreover, that there is no seasonal pattern to misery and depression at all. That hasn’t stopped a whole industry emerging from this “illness” selling light as a therapy.

Markku Timonen of the University of Oulu told me that “Typical SAD is not a psychiatric condition but rather a neurological state…it is a heterogeneous group of disorders of different etiology.” It seems too that sufferers manage their commitments but ignore their social life. In contrast, severe depression causes problems in all aspects of one’s life. If SAD is not true depression and has a multitude of causes and is not necessarily anything to do with winter, then why has a whole industry touting bright light therapy emerged?

Lamps with fancy names and even fancier prices have been marketed for several years as bright light therapy with claims of somehow stimulating whatever part of the brain thought to go awry when the sun barely crawls above the horizon. Most of these expensive gadgets are nothing more than bright fluorescent tubes but at ten times their normal price. There have been sporadic studies, but the countless claims for benefits smacks of a sCAM (spurious complementary and alternative medicine). There is even a Finnish study that shows in that temporally dark nation that more people are depressed in summer than winter.

Regardless, it’s inconvenient, isn’t it, carrying a bright light with you? So one company, Finland’s Valkee, has developed a device that looks like an innocuous portable mp3 player but rather than pumping beats it shines LED light into your ears. The company emphasizes claims that have been made that the brain is somehow photosensitive and responds positively to light reaching it via the ear canal.

Valkee earbuds

I asked a bio-physicist colleague to take a look at the Valkee device, which appears to be nothing more than a USB charging circuit two wires with LED earbuds and a timer-based on-off switch. He was not convinced that the LEDs were bright enough to get sufficient numbers of photons through the ear drum and the other tissues between the opening to the ear and the brain to have any significant effect. He was also skeptical that there are actually any functional light sensitive cells in the brain other than those that are hooked up to vision. The most direct route for bright light seems to be through the eyes and surely even the diffuse and clouded view of the sun seen between the Tropics and the Polar Circles in winter is greater than the photon flux from two small LEDs. But, as I’ve said the seasonality of SAD is murky.

Valkee suggests that their device shines away the winter blues with just 12 minutes each day. “[It] increases energy, and can act as a preventative or treatment of mood swings,” the company says. By the way, if it cannot be measured in Joules, it’s not energy. I asked Valkee’s chief executive Timo Ahopelto to explain further: “Light via the ear canal has an immediate stimulating effect in the brain,” he told me. However, depression is a disease that takes a long time to develop and a long time to cure. “Many antidepressants take 3-6 months to have an effect,” Ahopelto adds. “Although with some SAD sufferers we see an immediate effect after 1-3 days of usage, most typically the symptoms resolve after 1-2 weeks.”

Timonen has just published details of the trial (with no placebo) that shone light (6.0-8.5 lumens, equivalent to a 0.5 Watt incandescent lightbulb) using these earbuds in both ear canals for 8 or 12 minutes a day, five times a week for four weeks and reported back on the SAD volunteers’ depression scores. “During the study period, 12 out of 13 (92.3%) patients achieved at least 50% reduction in their HAMA sum scores, and in 10 out of 13 patients (76.9%), the HAMA sum score was <7,” Timonen and colleagues report. They assert that, “it is hard to believe that our findings could be explained solely by placebo effect.” However, without a proper placebo control they cannot be certain. Would it have been so difficult to stick unlit LEDs in the ears of 13 additional SAD sufferers for comparison’s sake?

I am not convinced that SAD exists. Certainly, as a loose measure of depression suicide rates are not seasonal and there is evidence that summer, when it is brighter, sees more mental health problems, although the picture is not clear. The best answer to the winter blues if you are able is to grab your hat and coat and get yourself outside into the fresh air and take a long walk. Get the available sunlight on your face even if it is behind the clouds, you’ll feel much better, I almost guarantee it.

David Bradley

David is a freelance science journal with more than a quarter of a century in the field. His best-selling book, Deceived Wisdom is available now.

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One thought on “Cloudy thinking on light therapy”

  1. I think I have had SADD since childhood, as I would have crying spells during the rainy season (grew up in the sub-tropics) and mother said my personality seemed to change then, as well. I figured out I had it as an adult. Used to have a day or 2 every fall when the seasons changed, of bad depression, even some passive suicidal thots…As I’ve gotten older the depression is much worse, and it’s more like a couple weeks of worse depression with the seasonal changes (I live where the winters get quite cold, now.) Plus I get worse after the holidays…usually have a bad spell around New Year’s…and also have had bad spells late winter/early spring. My diagnosis was upgraded to Major Endothermic Depressive disorder, and now I think it’s more like Persistent Depressive Disorder, (a blend of dysthymia and MEDD). Seasonal depression is definitely REAL. If you’ve never experienced it, how could you know what it’s like? And why are the Therapy Lights used by many medical professionals now as treatment? My SADD light was covered by insurance. They don’t cover things that aren’t known to be effective. (Altho the bright light irritates me and may aggravate the sleep problems…) Please don’t dis what you don’t understand.