Arkham Horror: Lovecraft Letter

You become Insane once an Other World card enters your discard zone; a card you played enters it only after its effect resolves. At the start of each later turn, before drawing, reveal cards equal to the number of Other World cards in your discard zone: revealing any Other World card knocks you out, while revealing only Arkham cards lets you continue (pp. 7–8).

No. If you’re Insane, you choose either the Sane or Insane effect; if you’re Sane, you must use the Sane effect. A card with no Insane effect uses its Sane effect (p. 5).

Usually, no: effects resolve when you play a card, not when it’s forced from your hand, placed directly in your discard zone, or revealed during a Sanity check. The Dilettante and Cthulhu are exceptions: their Sane effects also resolve when played or discarded from your hand (p. 6).

No. Its Sane effect protects you from being chosen by a card effect until the start of your next turn, but effects that hit all players still affect you (p. 12).

Players still in the round reveal their hands, and the highest-numbered card wins. If there’s a tie for highest, the tied players share the victory and each takes a Mythos token matching their state of mind (p. 8).

No. You’re out of the round only if you play Stowaway Eggs; discarding it does not knock you out (p. 15).