NIGHTMARES
Your character suffers from recurring and nearly incurable nightmares, stemming from an extremely stressful event or encounter in his past (or perhaps from some mysterious cause not yet explained).

[2 Pts.] Occasional Nightmares: There is a 35% chance per period of sleep that your character will experience extremely vivid and lengthy nightmares. The character must make a Will Save against a DC of 15; failure means that the character will be mentally fatigued the next day. While he can still run and charge, he will suffer a -2 circumstance penalty to Perception, and Knowledge checks, and he will suffer a -1 circumstance penalty to all of his attack rolls and Will saves. These penalties last until he is next able to sleep undisturbed.
[4 Pts.] Frequent Nightmares: There is a 65% chance per period of sleep that your character will experience extremely vivid and lengthy nightmares. The character must make a Will Save against a DC of 17; failure means that the character will be mentally fatigued the next day. While he can still run and charge, he will suffer a -2 penalty to Perception and Knowledge checks, and he will suffer a -2 penalty to all of his attack rolls and Will Saves. These penalties last until he is next able to sleep undisturbed.
Special: If the character is an arcane Spellcaster, this flaw is worth an additional two (2) Flaw Points. A bout of nightmares will rob the character of a single prepared Spell slot of each level he can cast for the next day. For example, if a character that can prepare two 1st level Spells suffers a bout of nightmares, he will only be able to prepare one 1st level Spell the next day.
Limitation: This flaw may not be possessed by characters that do not sleep.