What were the prescription rates in the 60s?
> the biggest rise in prescriptions during this time period was for back pain and other types of chronic pain.
Now I'm doubly surprised. Some benzos have muscle relaxant properties but I've never heard of them prescribed for pain.
(I've never experienced benzo withdrawal but I've heard it claimed to be as bad as opiate withdrawal.)
Benzo withdrawal can be much much worse than opiate withdrawal.
Opioid withdrawal is comparatively benign.
Which is a key for using such medicines for pain: You might be in pain, but you don't care. My understanding is that for folks allergic to anesthesia, they can literally relax them enough that the person doesn't care if they are doing surgery on them. They don't feel the pain either, but it isn't generally as convenient as folks being put under.
Back pain is thought to be mostly psychological, so it makes sense. Also, if you have minor tears or congenital defects in tissue around your spinal cord then anxiety can cause inflammation, which can then cause your spinal fluid to push against your actual spinal cord and cause all sorts of problems. (Or something like this, I'm not a doctor but that's the basic idea.)
Do you have a credibility source to back that up?
> After about ten years on the market, Valium had been prescribed to 59.3 million patients 
The US population in 1970 was about 200 million. A significant portion of the adult US population took valium at some point during the 60s/70s.
Ridiculously high because they were touted as safer alternatives to the then popular barbiturates. Benzos are safer, it just turns out that benzos also have not-so-great long-term effects.