There are those that do so today. Given we have no real mental health facilities, those people simply wind up in jail on drug possession charges. It's inhumane, yeah, but I don't think replacing things with UBI would make it more so. Maybe one of these days we'll actually get our act together to help those that need it most.

I assume with more 'normal' people being liberated from the yoke of work there might be more volunteers and volunteer initiatives to help those in need out. The question is how much of the self-destructive behaviour if a product of a 'sick' society where mental health treatment seems prohibited by the cost.