This is a fascinating video allows you to see some self-professed hoarders interacting with the possessions in their homes. The film implies its subjects are coping with obsessive-compulsive disorder (OCD). We deeply respect the courage it takes for a person with a brain imbalance to make a life for themselves in spite of it.
But I also want to stress that only a fourth of the people with overwhelming clutter actually suffer from OCD. Most people have simply become overwhelmed by some trauma tic life event that allowed clutter to get started.