I have found a new favorite TV show...Hoarders.
Show description: "Each 60-minute episode of Hoarders is a fascinating look inside the lives of two different people whose inability to part with their belongings is so out of control that they are on the verge of a personal crisis. Whether they're facing eviction, the loss of their children, jail time, or divorce, they are all desperately in need of help."
You can watch full episodes online.
Edited to add: I also found a documentary, My Mother's Garden, made by a daughter of a hoarder.