Dragon Sickness

Gold Sickness, also called Dragon Sickness or Gold Fever, is an apparent mental change that happens to someone caused by large amounts of treasure, particularly treasure hoarded by dragons. It results in greedy, illogical, and even violent behavior.

Hero: The Guardian Smurf stories
According to Papa Smurf, most trolls and Imps would suffer from such disease as they would be primarily focused on finding large hordes of treasure and nothing else. Papa Smurf warns his little Smurfs to never gather large amounts of treasure whatsoever as they could potentially come down with Dragon Sickness.