A hoarder doesn't see the same world as non hoarders. Some event has changed how they perceive things, usually a death or abandonment according to those who treat such things.

It isn't exactly the same as an addiction but there seem to be similarities.

Hoarders seem to have one advantage over addicts, in that they get positive feedback from starting to dispose of their hoards, as long as they do it and don't have it imposed upon them. The trick seems to be getting them started on the task by persuasion rather than force, and going over and over the information that the things they cling to are inanimate objects with little intrinsic value, until it sinks in.