From Compendium of Worldly Lore
Needs review
Source: Encyclopedia Arcane: Divination
Description: A curse to those who rely on physical might and agility, your spells target the mind as well as the body, making them much harder to resist.
Prerequisites: Ability to cast Illusion and Divination magic
Any spell with a range other than personal that offers a Fortitude or Reflex saving throw can be prepared with Psychic Spell. The spell gains the mind-affecting designator in addition to any that it might already possess, which may make certain targets immune to it when they might otherwise not be (undead, for example). A Psychic Spell has its saving throw changed to Willpower, although the other aspects of the save (half, negates, etc.) remain unchanged. Damage caused by a Psychic Spell is automatically subdual, though powers that reduce, negate or render a target immune to subdual damage do not apply.
Preparing a spell with this feat takes up a spell slot three levels higher than the original spell.