Here's one that came up sideways in a conversation I recently had.
Muscle Dysmorphia is a disorder in which the sufferer thinks he or she is not big enough. There is some disagreement about this being a "real" disorder or not, and who has it and who does not. But basically you can use it for shorthand for "never feels big enough." No matter how large the person gets, the mirror shows them someone they feel just isn't muscular enough.
This isn't an excuse to call anyone trying to get bigger a person with a disorder, but it's handy to know the actual term for the problem.
2 hours ago