I've lately been listening to Mary Roach's book "Stiff" on my daily commute, a fascinating (and often stomach churning) book about all things cadaver-related. One chapter covers the history of attempts to resuscitate cadavers and heads (freshly guillotined!). The next moves to attempts by surgeons to transplant living heads (on animals thus far, though I'm not yet finished with the book).
One comment in particular caught my ear. She mentions that people in sensory deprivation chambers invariably hallucinate and ultimately go mad (relating to the fact that a detached brain, if kept alive, would most likely suffer a degree of sensory deprivation with similar consequences).
Another book on my recent list (Pandora's Seed, by Spencer Wells) discusses the rise in mental health issues in modern society, to the point that mental health issues are expected to be the second leading cause of death in the US by 2020.
Could widespread sensory deprivation be the cause of our mental health issues? Absolutely.
We already know that our immune systems "go mad" when they're deprived of frequent exposure to irritants and pathogens, resulting in a massive increase in allergies and autoimmune disorders, to the point that many children now risk sudden death from the exposure of a single drop of peanut oil or milk on their skin. Researchers have discovered that Amish children, who frequently live on farms with livestock and often go barefoot in the summer (both likely sources of exposure to pathogenic bacteria), have very low allergy rates. Coincidence?
So how are our lives like sensory deprivation chambers? Consider the life of any human before the industrial revolution (or better yet, before the advent of agriculture), and contrast that with our daily lives now. The pre-industrial human spent the majority of their time outdoors, directly experiencing everything from extreme temperatures to wind, rain, and all the weather that we nowadays just view from the comfort of our climate controlled car/home/workplace.
Their daily activities were highly varied. They used their hands, not machines. They hunted and gathered wide varieties of food (leading to better nutrition -- human stature dropped significantly once we became farmers), travelling through all sorts of terrain. They built their own homes. Schooled their own children. They did everything that you and I now pay others to do for us, either directly or otherwise. Nowadays, most of us repeatedly perform a single specialized task for which we receive money, typically performed within a climate controlled building while sitting still. It's boring.
So to relieve the boredom, we go home, sit, and turn on the TV, computer, or game console. We don't make our own entertainment, as pre-industrial man would've done. We've outsourced damn near everything.
The net effect of trying to avoid physical work and make ourselves comfortable is that we've turned down the volume on life -- moving ever closer to the point of complete sensory deprivation. The compartmentalization of our lives and careers has deprived us of varied and essential experiences. It's no wonder that both our bodies and minds are going nuts.
Get rid of the fossil fuels, and I suspect these ills of modern society will go with them.