Compulsive hoarding is defined, in part, by clutter that so overtakes living, dining and sleeping spaces that it harms the person’s quality of life. A compulsive hoarder finds it impossible, even painful, to part with possessions. It’s not clear how many people suffer from compulsive hoarding, but estimates start at about 1.5 million Americans.

Image Credit... Nola Lopez

Dr. Tolin recently studied compulsive hoarders using brain-scan technology. While in the scanner, hoarders looked at various possessions and made decisions about whether to keep them or throw them away. The items were shredded in front of them, so they knew the decision was irreversible. When a hoarder was making decisions about throwing away items, the researchers saw increased activity in the orbitofrontal cortex, a part of the brain involved in decision-making and planning.

“That part of the brain seemed to be stressed to the max,” Dr. Tolin said. By comparison, people who didn’t hoard showed no extra brain activity.

While hoarders are a minority, many psychologists and organization experts say the rest of us can learn from them. The spectrum from cleanliness to messiness includes large numbers of people who are chronically disorganized and suffering either emotionally, physically or socially. Cognitive behavioral therapy may help: a recent study of hoarders showed that six months’ therapy resulted in a marked decline in clutter in the patient’s living space.

Although chronic disorganization is not a medical diagnosis, therapists and doctors sometimes call on professional organizers to help patients. One of them is Lynne Johnson, a professional organizer from Quincy, Mass., who is president of the National Study Group on Chronic Disorganization.

Ms. Johnson explains that some people look at a shelf stacked with coffee mugs and see only mugs. But people with serious disorganization problems might see each one as a unique item  a souvenir from Yellowstone or a treasured gift from Grandma.

Many clients have already accumulated numerous storage bins and other such items in a futile attempt to get organized. Usually the home space is adequate, she says, but the challenge is in teaching them how to group, sort, set priorities and discard.