You send wracking pains through the targets' bodies. Because of the pain, affected creatures take a –2 penalty to AC, attacks, melee damage rolls, and Reflex saving throws, and must succeed at a concentration check (DC equal to the DC of this spell) to cast spells. However, if an affected creature spends a move action screaming as loudly as possible, it can act without any other penalties for the remainder of its turn. “Screaming,” for the purposes of this spell, includes any vocalization of pain or its telepathic equivalent; creatures that cannot scream (such as creatures without the natural ability to communicate or vocalize) suffer the full effect of the spell.