[Taqwus]

Insanity appears to be currently quite irreversible, unless they've silently added a cure in the 3.06 patch. Only Void creatures are immune.

The freespawn do add up. Keep 'em moving, and don't worry if they catch a lot of arrows. I once overwhelmed a pretty entrenched AI Jomon (most of my illithids and summons were on other fronts -- was simultaneously conducting large-scale invasions on three different continents) by drowning them in lunatics.