Enrage an opponent to a point of no casting?

[TheCreatorT]

Is there a way to enrage/distract an opponent so much they can't spell cast? If so, is it effective at all?

[Larsen]

In pathfinder, there is the Incite Rage from the bard archetype savage skald (http://www.d20pfsrd.com/classes/core-classes/bard/archetypes/paizo---bard-archetypes/savage-skald).

Since it functions as a barbarian rage, it means the target cannot cast spells.

[Necroticplague]

Is there a way to enrage/distract an opponent so much they can't spell cast? If so, is it effective at all?

Yes. The Rage spell acts as the barbarian rage, which means no casting. However, given how it has a duration of concentration, and immunity to it is only marginally less common than air, effectiveness overall is questionable.

[Larsen]

The rage spell alone is only on willing creature, I don't think the intended target is a willing one.

[Telonius]

The "Enrage Enemies" feature of the Divine Prankster PrC is similar to the Rage spell, and forces the target to pursue and target the Prankster with melee attacks (or stand screaming in futile rage if they can't close). It does have a few benefits that the Rage spell doesn't; it doesn't grant the target extra constitution, attack bonuses are against the caster only, it's a Supernatural ability (so not subject to Spell Resistance or Dispel, and the caster doesn't have to worry about Attacks of Opportunity), and multiple targets don't have to be within 30 feet of each other. It's still Mind-Affecting, but is a Charm, not a Compulsion. (Unfortunately most things that make you immune to Compulsions also give immunity to Charms, but there might be some edge cases where it would matter). On the other hand, it does offer a save (DC = Perform check) and it ends if the target is attacked.

[fishyfishyfishy]

There's a buzzing bee spell in the Spell Compendium that creates a bee near the opponent that forces a concentration check every time they attempt to cast a spell. The DC is low so it's only partially effective even at lower levels.

[Draco_Lord]

There is also the Heavens Mystery for Oracles in Pathfinder. They have an ability called Mantle of Moonlight which lets them use a melee touch attack to force others into a rage. And since casters kind of suck at avoiding melee touch attacks if you can get close, it can be lots of fun. My favorite use of that involved my Rage Prophet picking it up, and basically shutting down a caster that was meant to be a challenge by flying right at her and using it.

[Inevitability]

I can't believe Mindless Rage hasn't been mentioned yet. It makes an enemy want to kill you, but only in melee, without using spells. That's enough to shut down most casters completely, unless they're all CoDzillas and Gishes.