One of the many make-it-ups I've seen.
It could simply mean they lose their next turn; or you might make them roll on mini-confusion table.
1. you're not sure where you are or what you are supposed to be doing. Miss your next turn.
2. reality is fractured; you don't know friend from foe. Attack nearest living creature be it friend or foe. If more than one creature at same distance, roll randomly.
3. you hear the bell toll and must wander toward the imagined sound. You seek to walk away from combat without regard to defense and ignore attacks against you as you stumble in a random directly for 1d4 rounds. Let's hope your friends are alive and willing to protect you.
4. you've forgotten how to fight. All rolls to attack and defend have +2 DR for duration for next 1d6 rounds.