The distinction between truly pathological hoarding, which can reach psychotic levels, and the type we call the packrat (or "the disposophobe") is more a matter of degree than intrinsic difference.
If you live with one of those, you often despair of ever putting your own living space in order, while the companion who "saves" useless objects shows no inclination to reform. He may tolerate your cleaning out the mess from time to time, but the accumulation will return.
I regret to have to tell you that the science for this kind of disorder is as yet inconclusive.
There seems to be two different avenues of research; one looks at the biology of this family of disorders, the other at its emotional aspects.
From the standpoint of brain biology, faulty thought processes are involved. The packrat fails to recognize his behavior's negative impact on his and others' quality of life. His ability to organize, classify and realistically appraise his possessions is impaired.
Some studies connect hoarding with the cerebral differences of ADD and the under-functioning of the executive parts of the brain. The hoarder has trouble making decisions and choices. Certain psychotropic medications have been used with a modicum of success.
They are the SSRI family of antidepressants such as Paxil. Results are unpredictable and limited.
Cognitive-behavioral therapy, which targets faulty thought and behavior changes, has proved the most helpful approach. CBT is practiced by specialized therapists. It consists of very structured techniques focusing on change rather than on history...." More