Level 16 DiseaseMindfire

In the initial stages, victims of mindfire complain of burning pain in the head. Later, they sink into stupor.

Stage 0: The target recovers from the disease.
Stage 1: Initial Effect: The target gains vulnerable 10 psychic until cured.
Stage 2: Each time the target becomes bloodied, it becomes dazed and takes ongoing 10 psychic damage (save ends both).
Stage 3: Final State: The target is dazed.
Check: At the end of each extended rest, the target makes an Endurance check if it is at stage 1 or 2.
19 or lower: The stage of the disease increases by one.
20-24: No Change
25 or higher: The stage of the disease decreases by one.

Published in Dungeon Master's Guide, page(s) 50.