I was once placed on a medication that went too far that direction... where I couldn't break out of the single thought path. Where driving was enough of a distraction, that where I was going would slip by, and I had to circle around multiple times. And I had once lost three hours of time and have a couple hundred tabs open in my browser as I started reading an article, then just kept stearing through, etc.

I was encouraged to stick with it for a month to see if it normalized, it didn't... I don't even remember the medication, but would never want to experience that again... I'll take the half dozen to dozen stray thoughts in my head at once... I'm far more effective that way. Though stress makes it hard to get/stay asleep.