We have run into an NPC who we have determined is under the effects of Sow Thought.
How do we snap him out of it? I see the Break Enchantment spell. Any other ways?
"The target genuinely believes that the idea is his own, but is not required to act upon it."
I'd try talking him out of it. Failing that, Dispel Magic should be sufficient.
Assuming the creature that cast the enchantment on the NPC was evil, spamming Protection From Evil will eventually do the trick, for a short time.
If not evil, another short duration possibility is the Suppress Charms & Compulsions spell. Any time it's plausible I love picking up a CL 4 scroll of it, typically for countering Confusion or other random effects. Second level means you can prep it early in any game, or buy a CL 3 scroll if still too low of level. Anyway, even 10 minutes of non-compulsion could cast enough doubt on the implanted idea to negate it.
Then if any clerics in the area have the Chaos: Azata subdomain, that gives rerolls vs enchants from level 1. Same thing for the Glory: Honor subdomain.
A more elaborate setup might be to have a spellcasting local the NPC would trust, like a priest, cast the level 1 spell Detect Charm. He could even add a Zone of Truth spell to give evidence he isn't lying.