Wikipedia has more on Disposophobia
Disposophobia (from the Latin word dispos, meaning "getting rid of personal belongings", and Greek phobos, "fear") is the fear of getting rid of or losing things, resulting in an act of hoarding. The phobia is often caused by a neurological disorder or a past traumatic experience, such as throwing something out, only to have regretted it later, loss of loved ones or jobs, and divorce. Sufferers of disposophobia would want to save every small thing acquired, including receipts, old magazines, worn out clothes, newspapers, old mail, lists, notes and so on.
People with disposophobia often have trouble organizing things. They display intense anxiety and fear when asked to throw out old and unwanted/unnecessary stuff. They might show following signs of anxiety/panic attacks with symptoms of restlessness, rapid breathing and heartrate, screaming, running away or hiding rather than throwing away the stuff, getting extremely distressed, and becoming nauseated at the thought of getting rid of stuff.
The houses where disposophobe lives are often cluttered everywhere. Animal hoarders tend to live in extremely unhygienic/unsanitary conditions; their living spaces are often home to bacteria, rotting food, vermin, rodents and even biohazard waste. If there is open space, sufferers may feel restless while thinking about filling in with old stuff.
People with mild disposophobia is often treated using talk therapy and other psychiatric interventions. Severe sufferers are often treated using anti-obsession medication, as well as cognitive-behavioral therapy.