Jibber Jabber

Jibber Jabber is a magical illness initially brought on by use of zone of truth or truth serums. A creature subjected to these effects run the risk of developing Jibber Jabber. Despite its name, Jibber Jabber is no laughing matter. Many a folk whose caught Jibber Jabber ends up dead.
Jibber Jabber compels a creature to speak non-stop for the duration of the illness. When faced with somebody they are keeping secrets from, the affected must reveal any truths regarding them.
The first time a person catches Jibber Jabber, it lasts for twenty-four hours. The second time, forty-eight to seventy-two hours. If you catch it a third time, it is permanent until you find a magical medical practitioner to remove the effects.
Typically, folk who catch Jibber Jabber place themselves in isolation until the effects pass. Although the effects of Jibber Jabber itself are harmless, the fallout can be deadly. Speaking non-stop can be tiring; people run the risk of sore throat, dehydration, and exhaustion. More troubling, Jibber Jabber can turn friends into foes.
Betrayal can lead to injury or death.
These fights can transform into an intense battle of words and swords, with multiple layers of truth being revealed by each party into a Death Brawl.

You can't handle the truth!

by Brgfx

Easily Spread: If you're not careful, you can catch Jibber Jabber from another. If a friend or foe has Jibber Jabber, you better put on your best poker face. If a truth they reveal causes you to react with any emotion--be it anger, sadness, envy, or joy--you will catch Jibber Jabber from them.

Prevention

The only way to protect yourself from Jibber Jabber is to never come under the effects of a truth spell or serum. And to never be around somebody who has been afflicted with Jibber Jabber. There are some potions and spells that can increase your resistance against mind effects, such as truth spells and serums.

Treatment

Treatment for Jibber Jabber can be costly. Those who can treat it are rare, except in larger settlements. Notably, Tifwado City has magical medical practitioners at The Hideaway: Enchanted Renewal Spa, who specialize in removing magical illness, such as Jibber Jabber. To do so, these practitioners manipulate energy in the afflicted's body through light and deep pressure touches.
Most people choose to talk out the illness in seclusion, rather than risk public travel to find somebody who can cure it.
If somebody has permanent Jibber Jabber, they will need to find a magical medical practioner, such as those who work at The Hideaway, in order to heal the effects.