• Akrasia

Sufferers do things despite thinking they're bad decisions. They tend to be things that bring small amounts of happiness in the short term, but other times they seem to do nothing more than alleviate boredom. Some examples are simple games, and classifying literary devices. It's not uncommon for the victims to spend most of their lives on unproductive things.

• Antipleasure

Antipleasure is a rare disease in which a victim's happiness is so low that they would prefer the events not have happened in the first place. Not simply that it's replaced with an average event, but removed altogether. It can be short but powerful, commonly triggered by physical damage, long and weak, generally triggered by psychological issues, or in rare cases, long and powerful, triggered by such things as kidney stones and jellyfish venom. In extreme cases, sufferers have been known to take their own lives.

• Inherent Limit

This affliction causes the victims to atrophy. The damage gets more extreme, eventually leading to death. No victim has ever survived longer than 122 years.

• Inevitable Cessation

People afflicted with this syndrome can generally heal from small wounds, but large enough wounds, along with several other possibilities, lead to them degrading into inert matter. The victims go to great lengths to postpone this unimaginably horrific fate, but it's believed to be impossible to prevent completely.