Well. Time for him to try and explain a concept Dimitri is not entirely certain he can explain right himself.

"It is... sadness, as an affliction," Dimitri tries slowly, although he wonders if that makes sense. "Sadness that haunts a person, no matter if their life is going well, or if they are doing something they know they love. It keeps them locked in misery... or apathy, and exhaustion. It tricks them, in numerous ways, such as thinking they are a worthless existence, or that they'd rather not live."