As discussed in my review of the Pathfinder RPG Bonus Bestiary, not every 3.5 Monster Manual monster will be in the first Pathfinder RPG Bestiary. Some were passed over for being too niche, others because they were not open content.
More than any part of our bodies, we associated who we are with our minds. An attack on our minds is more than just anassault on our body, it is an assault on ourselves. Perhaps that is what make Thought Rippers such terrifying creatures; first they take over our minds, then they feed off them.