Emotive Block

You create an emotional block in the target’s mind, adding an emotion component to each spell or spell-like ability he uses. This is in addition to any other components the spell already requires, and doesn’t replace the somatic component. The target’s spell-like abilities require this emotion component, even though they normally don’t need spell components.

As usual with emotion components, the target can’t cast spells (or use spell-like abilities, in this case) while affected by a non-harmless emotion or fear effect.