Non-lethal damage disrupt spell casting?

[blue_the_wolf]

if a person happens to ready an action to punch a spell caster in the face if he casts a spell.
caster tries to cast and gets punched in the face for non-lethal damage

does the non-lethal damage from the sap force a concentration check just like lethal damage?

[MurphysParadox]

Pretty sure it would. It is damage, after all, and I don't believe concentration calls out 'lethal damage' specifically.

[Arbane the Terrible]

I'd say so. Try reciting the Declaration of Independence while someone hits you in the face with a pillow, and let me know if you mispronounce anything.