I have been fascinated with the effects of solitary confinement on mental health. Why the Covid pandemic has added horrors is because large parts of human populations are under virtual imprisonment, not being able to visit and touch friends and family, and not being able to travel. Anecdotal evidence strongly indicates that this had vastly detrimental effect on mental health.

(Understanding this may be also crucial for the proper design of long-duration space travel.)

Just like ordeal by fire, and ordeal by boiling oil, I wish that solitary confinement be identified as cruel and unusual punishment, used sparingly and only with the highest levels of bureaucratic clearance. Probably only against the insanely violent, rather than the mildly inconvenient.