An article from New Scientist in 2003 said that damage in a certain part of the brain leads to compulsive hoarding, by giving free rein to the dim satisfaction of squirrelling things away.
Steven Anderson of the University of Iowa and his team studied a group of pathological collectors. They found that damage to the frontal lobes of the brain impaired judgement and caused emotional disturbances. But only when the injury extended to the right mesial prefrontal cortex, a tiny region of our prefrontal cortex, did the patients develop a serious collecting habit too, Anderson told a meeting of the Society for Neuroscience in New Orleans this week.
Previous work in rodents shows that more primitive, subcortical brain regions produce the drive to collect food or useless objects. No matter how much they have stashed away, animals will just go on collecting. We have the same basic drive, says Anderson. But the right mesial prefrontal cortex can normally discriminate between something of value and something that’s useless, and keeps the drive in check. When it is damaged the more primitive collecting drive comes to the fore.
Hoarding is associated with obsessive-compulsive disorder.
Hoarding is a compulsion that results from excessive concerns that certain objects cannot be discarded because they might be needed later. It may also involve excessive acquiring, such as compulsive shopping, extreme collecting, or acquisition of free things (e.g., free newspapers, pens, junk mail). Hoarding can be a result of severe indecisiveness over what items should be kept versus discarded; the hoarder simply cannot decide, so decision is avoided and all is kept. Hoarders also have difficulty figuring out how to best organize those items which are kept; as a result, the hoarder amasses piles of disorganized objects.