I remember a book I read possibly in the 70s or 80s, about a galactic cloud that had moved to expose Earth to something (the Radiant?) that could give people mind powers. But many people experienced the radiant as pain and madness.
The radiant was some kind of cosmic good; people who could open their minds to it experienced a great well-being (maybe also communication with each other?). There was propaganda against this power - a few twists in the story where one wasn't sure if it was beneficial or harmful. There was a scene in which the "girlfriend" character's father slipped in the shower and was yelling blue murder about having hurt himself, but she phoned Our Hero and told him her father had got the madness.