Preprint is out! 100,000 lumens to treat seasonal affective disorder

by Fabienne1 min read12th Nov 20216 comments


LightingTherapyDepressionWorld Modeling

Let’s give people with winter depression (seasonal affective disorder, SAD) LOTS OF LIGHT and see what happens!

Our preprint is out now for our paper “100,000 lumens to treat seasonal affective disorder: A proof of concept RCT of bright, whole-room, all-day (BROAD) light therapy”! We have sent it to a number of professors working in that area and have received very encouraging and helpful feedback, which has made me even more excited about continuing this research.

→ Paper:, short summary Twitter thread: 

Jan Brauner and I are very thankful to the LessWrong/EA communities, which have inspired this first study (there will be more) and through which we have found funding. In particular, thank you Eliezer Yudkowsky for helping us find funding and for inspiring the study with Inadequate Equilibria, David Chapman for inspiring us with these two posts in the Meaningness blog, Raemon for inspiring us with this LessWrong post and everyone who discussed with us setups they have tried. <3

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Woo! Congratulations.

I participated in this study, with full-room illumination of 60.000 lumens and 6 hours per day of treatment. The effect was remarkable. Throughout Winter 2019/2020, I did not feel depressed or lethargic on even one single day on which I used the setup correctly. I did feel depressed 2-3 times per week in the weeks prior to starting treatment. And I felt depressed on some of the days where I did not use the system.

Here's what surprised me: Throughout the winter I went hiking in direct sunlight for 3 hours each day. And my office had really big windows with unobstructed view of the Sky. And that still wasn't enough to fix depression. By adding 6h of light therapy per day on top of that, my winter depression vanished.

I am amazed that such a simple, cheap and side-effect-free intervention has such a big effect. On top of that, such whole-room illumination is really pleasant subjectively and makes me feel as if I'm sitting outside. When friends suffer from SAD, light therapy is the first thing recommend.

What do people think about the effects of such bright light on skin? I have heard anecdotally that some SAD lights can cause sunburn. The long term oxidative effects may not be desirable, either aesthetically in terms of skin ageing, or for health in terms of skin cancer risk. 

The health effects of stress/loneliness/depression and sheer subjective misery are powerful counter-arguments regardless.

I'm currently in the middle of building a light setup based on this one by David Chapman of Meaningness. Wearing sunscreen is one option I've been considering! Would be interested to hear if anyone has experiences to share.

I think sunburns are usually caused by UV light, and normal indoor LED lighting shouldn't put out much UV even at high intensity.

I experimented with using a very powerful halogen bulb (double envelope for safety) positioned as close as possible to my face and it seemed to work quite well, it really did feel like a summer afternoon if I closed my eyes. It’s a remarkably simple thing to do too so developing a more convenient system would seem to be highly useful. 

Great job on this paper.

I'm trying to replicate the experimental set-up at home, anyone know what kind of string lamp to buy? All the ones I've seen seem to not be bringht enough, but maybe I've done the Lumen/watt/volt conversion wrong...