Some highlights:

Hoarders were found to have lower activity in a specific part of the brain that’s involved in decision-making, focused attention and the regulation of emotion.

"This pattern was not seen in other OCD patients, nor in the normal controls. It looks like compulsive hoarding is truly a distinctive diagnostic category, which has big implications for both diagnosis and treatment."

10 compulsive hoarders underwent cognitive behavioral therapy, which included 26 individual sessions and frequent home visits. Following seven to 12 months of treatment, 50 percent had "very much improved" when it came to classic hoarding behaviors like the clutter, excessive acquisition and the inability to discard.

"Hoarders have a fundamental inability to keep things organized," says Frost. "Not just their possessions, but other things, like finishing tasks. We see a lot of attention deficit problems in hoarding."

Christiana Bratiotis, research assistant and therapist for the Compulsive Hoarding Research Project at Boston University, sees task forces that combine mental health services with local enforcement agencies as "the ticket" to helping many hoarders.
"We have someone with the big stick saying you’re in violation of public health and safety codes and then we have the carrot, a social worker or public health nurse who tells them ‘We’ll advocate on your behalf and help you stave off an eviction while you’re in mental health treatment.’ That’s where we’re seeing lasting change."

and

"Not just their possessions, but other things, like finishing tasks. We see a lot of attention deficit problems in hoarding."

Interesting.

SIL hasn't been diagnosed with ADD, but her brother has. She has severe PMS, and one of the components is an inability to make decisions.

She can't clean her house because she can't decide where things should go.