You’re correct about there being a distinction between major depression for example and being wholly apathetic, they created a separate diagnosis and treatment plan for it.
Because it’s not depression, it’s actually something called dysthymia, which was removed from the dsm in recent years but, there are people who have had this issue. It’s, different than depression... i will try to find a video on it i remember seeing that helped me understand the distinction and what it was like.