When a character takes Sanity damage, he must test to hold his composure while his mind deals with the warping effects of Sanity loss.
Whenever a character takes at least one Sanity damage, he must test Will + Nerve. The difficulty of this roll is equal to the amount of Sanity damage taken, minus the Character's Composure ability. If the character fails this roll, he is Shocked for a number of rounds equal to the damage taken. If the character botches this test, the character is Broken for the same duration instead, and must test versus Temporary Insanity as if he had 9 Sanity remaining.