Actually, they didn't touch the lights at all, they only measured the lights that people already were exposed to. They write that "an interventional method, such as a randomized controlled trial using a LAN exposure, is not possible because of ethical concerns".

If "ethical concerns" prevent even this mild and useful intervention, ethics has turned into anti-science paranoia. There has got to be a middle ground between mad science and today's bureaucratic IRB busybodies.

It seems like giving half the people blackout curtains and then monitoring depression levels would be perfectly ethical, since it's expected to improve their life, if anything.

The problem with that is the placebo effect..

There are ways to set it up with an alternate/sham treatment for the control group (maybe some nice pictures to hang on the wall--something equally decorative but not light-blocking). It's not perfect because there's no way to make it fully blinded, but the results would still be a substantial improvement over the existing observational study discussed in the article here.

But the proposal was for a single-blind study in which half would have some other placebo, I take it.

> Actually, they didn't touch the lights at all, they only measured the lights that people already were exposed to.

But isn't it a flaw of the study? It only shows correlation without causality. What if being exposed to light is correlated to some other factor that is responsible for increased depression? In this case, decreasing the amount of light won't decrease depression.

It’s a limitation, not a flaw. Ethical concerns limit a lot of studies. It’s not generally considered ethical to induce depression in human subjects.

But yes, it’s possible that some other factor is responsible, such as living next to a busy road with lots of street lights.

Sorry for the confusion, I forgot to specify that I was giving an answer to the following:

> they only measured the lights that people already were exposed to

I can’t imagine minor adjustments to light levels could ever be considered unethical. Is it unethical when a city installs a new street light?

It’s unethical to do X when X is expected to harm the study subjects. Exceptions are sometimes made for interventions with terminally ill patients, but in general studies that are expected to harm subjects are not approved by ethics boards.

They could reasonably do an intervention study that only reduces bedroom light to confirm if that corrects depression on subjects.

Other studies have shown increased risk of cancer for nurses that sleep during the day, so there is a legit concern.

Yes - it is harmful, we now know, and keeping people in solitary confinement with high light levels around the clock even more so, although common.

> They write that "an interventional method, such as a randomized controlled trial using a LAN exposure, is not possible because of ethical concerns".

They're wrong about that. The intervention group could be advising people to avoid light, and having someone come to their house and install better shades and put tape on LEDs.