Type insanity; Save Will DC 20 Onset immediate Effect –4 penalty on Will saving throws and all skill checks; loss of memory (see below)
A character suffering from amnesia cannot remember things; his name, his skills, and his past are all equal mysteries. He can build new memories, but any memories that existed before he became an amnesiac are suppressed.
Worse, the amnesiac loses all class abilities, feats, and skill ranks for as long as his amnesia lasts. He retains his base attack bonus, base saving throw bonuses, combat maneuver bonus, combat maneuver defense, total experience points, and hit dice (and hit points), but everything else is gone until the amnesia is cured. If a character gains a class level while suffering from amnesia, he may use any abilities gained by that class level normally. If the class level he gained was of a class he already possess levels in, he gains the abilities of a 1st-level character of that class, even though he is technically of a higher level in that class. If his amnesia is later cured, he regains all the full abilities of this class, including those gained from any levels taken while he was suffering from amnesia.