This is going to come as a shock, but most people have hoarding tendencies. Our bodies are literally designed to hoard calories in case of famine.
True hoarding is a serious mental disorder, and as one of the other posters noted, related to Obsessive Compulsive Disorder. Like OCD, it focuses on control issues. It can take many different forms, and there is usually a triggering traumatic event when the hoarding is isolated to a few specific categories.
For example, one show featured a mother whose stillborn baby had died more than 10 years before, yet she still couldn't let go of the clothes, toys, and other items associated with her child. She had not been able to process her grief. Working with the counselors on the show, she not only was able to give away most of her child's possessions, but also work through her grief.
"Possibilities" is another version. A "found art" artist saw possibilities in everything, and would pick through trash for salvageable items. If you have a box full of craft items, scrapbooking supplies, etc. just waiting for that day when you'll have a chance to work on them, you fall into this category.
Another form is the "what's normal" variety. Your parent/s were borderline hoarders, so having tons of stuff around was SOP. Most of these folks aren't true hoarders--just disorganized. Yet they can also put their hands on what they're looking for.
One reason hoarding is associated with older folks is because of the Great Depression. Certain items were hard to come by, so to throw out anything still useful was practically a sin. For years, my mom would collect bacon grease in a tin can in the fridge only to toss it out when full. I asked why, she didn't know and asked her mother, only to be told it was for the war effort. The World War II war effort.
True hoarding is measured by the amount of distress is causes the victim. As incredible as it might seem, to throw a toilet paper tube away can cause the same level of anxiety as murdering a kitten. No, it doesn't make sense, but that's because these poor folks are living with impaired judgement. Anti-anxiety meds can help, but most of the therapists on the show start with Cognitive Behavioral methodology. Because control is such a huge issue, this particular therapy allows the patient to make conscious changes themselves rather than being forced into something.
Most hoarders do not like living like this. It's a constant battle for control over their environment versus their need for safety (think Doomsday Preppers). Many would like to clean, but are so overwhelmed they don't know where to start. They're also afraid they might inadvertently throw something valuable away. That's why the therapists are there to guide them through the process. It is extremely difficult to overcome on your own.
Animal hoarders are an entirely different category. They begin with good intentions--rescuing unwanted animals. These are usually substitutes for a lack of human companionship although there have been cases where the hoarders are close relatives like mother and son. You rarely find animal hoarders having other appropriate social outlets.
Unfortunately, because they usually lack the funds to adequately care for living creatures as opposed to inanimate objects like dolls--another common human substitute, the animals begin to suffer from the neglect. But being animals, they still offer unconditional love. Despite what the letter of the law may say, there is a vast difference between neglect and abuse. Just ask anyone who has seen the results of a dogfight.
In the US, mental disease is still a stigma and many folks will not seek treatment. And to be honest, there aren't that many options available for hoarders. Animal hoarders are most likely to be prosecuted and forbidden or limited on the number of animals they can own. But this doesn't stop the "urge" to rescue, or fill the love gap these people feel.
We just have to do our best and not enable these folks if possible.
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