By David Wade, WBZ-TVBy David Wade

BOSTON (CBS) – It’s a secret hidden behind closed doors, but millions of people are driven to collect things most of us consider junk, even trash.

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Reality TV shows like “Hoarders” have made us aware of the lives these people lead, but they haven’t answered why they are compelled to live this way.

Researchers are now finding more evidence there could be a genetic link.

It is estimated up to six million American could suffer from this pathological brain disorder.

“Amanda” was one of those hoarders. “I was obsessed with this, truly obsessed,” she admitted.

She hoarded old TVs, furniture, paper, stuffed animals, and just about anything else she could find. “Literally, I had to sometimes push items on my hands and knees down the hall, on the floor, to get them in here.”

Storing so much stuff can turn deadly. 85 year old Joseph Kozlowski, a WWII veteran was trapped in the basement of his Wayland home in March as piles of debris smoldered. He lived in the basement because he could no longer access the upper floors of the house. They were packed with junk.

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One neighbor said, “If you wanted a newspaper from 1938, you would go see Joe.”

Wayland Fire Chief Vincent Smith said this was one of the worst cases of hoarding he has ever seen.

Fighting a fire is always a tough job, but the lack of access to the fire and the victim made this situation even worse.

Chief Smith said investigators scraped their heads against the ceiling because the piles of debris and junk were so high.

So why would anyone live like this? Researchers have mounting evidence a hoarder’s brain is wired differently. They are finding some clues on chromosome 14.

Dr. Gregory Chasson, a psychologist, explained “Research coming out suggests that there is a genetic component and what that means is there is definitely a biological component.”

Amanda sought treatment, and discovered a link to her past. “I’ve come to learn very shockingly, my father was stashing and storing everything, either in storage in his building or in closets.”

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Amanda’s treatment involved prolonged work with a therapist, who came into her home to help her let her clutter go. They also worked on some other underlying psychological factors as well.

David Wade