Cause and effect isn't necessary to reduce harm. You with me? It's nice to have certainly, but it is not required.
Imagine that I am a friend of yours. I tell you that my child is depressed and the doctor suggests pill1, it makes my child more lethargic. We try pill2 and the depression is gone.
I tell you that I am happy with the results of pill2 and that while I am interested in how it works and potential long-term consequences, I'm happy staying on pill2.
Is this imagined parent strictly better than a parent that refuses to try any pill until convinced of its mechanism and success? I would say yes.
Observation is the workhorse of the scientific paradigm, not idealized experimentation. The quantity, and thus value, of Inductive evidence is greater than that of Deductive evidence.
Which would you value in your medical care professional?
Measure what you value and optimize for it. Why do this devils advocate stuff?
As if there aren't uncountable other variables that have changed dramatically over millions of years. Or hell, do you even know if suicide rates are higher today than they were millions of years ago? No. You came here to try to suggest city living was inferior to rural living, and used "millions of years of evolution", and some implication that modern rural life is somehow more similar to those millions of years than urban life.
Then what does this suggest? Why does "unnatural light" (ignoring that humans have built "unnatural light" fires for ~1.7 million years) make a brain go haywire, but not, say, clipping one's toenails? Or reading books, or sitting on chairs, or being blasted by radio waves, or running on treadmills, or traveling over 15mph, or wearing clothes, or flying in airplanes, etc. What are you saying?
Health effects of radio waves: https://www.fcc.gov/engineering-technology/electromagnetic-c...
Artificial light exposure and circadian rhythm: https://www.ncbi.nlm.nih.gov/pubmed/30311830
I'm saying exactly what I said - there are some aspects of an urban technological life that are harmful to the human body
Edit: I guess I'm being pedantic at this point. My personal position is industrial agriculture is failing rapidly and that the modern world will reconcile with the fact that either we will all starve, or learn how to farm again. I spend half the year working on an organic farm, and my life is immeasurably better than when I'm in the city (which is of course, only my personal subjective datum which and I realize how much HN hates anecdote as evidence)