As a child, Liz C. remembers having "heart palpitations" whenever the doorbell rang. Usually, she'd meet friends outside rather than let them see the stacks of newspapers, boxes, used paper towels and other trash cluttering her family's home in Short Hills, N.J.

"My mother would tell me to lie. She'd say, 'Tell your friends we're painting—that's why all these boxes are here.' How sick was that?" says Liz, who asked that her full name not be used.

By age 11, Liz was working to buy her own food and clothing. "You expect your parents to have food for you, but the kitchen table and counters were just cluttered with garbage," she says. Yet her mother rebuffed any offers of help, and her father, an alcoholic, didn't want to upset her. "It was a mutual enabling situation," says Liz, who is 50 years old and works in marketing at a New Jersey university.

Her mother now lives in a retirement community and, at 80, is still hoarding. "She'll never change," Liz says. "The psychologists say you have to forgive to move on, but it's hard, especially when you have to visit and you still think, 'Jeez—look at this mess!' "

Compulsive hoarding—accumulating so much stuff that one's living space is rendered unusable—is coming out of the closet these days, thanks to books, movies and TV shows like A&E's "Hoarders." (I first wrote about it in my Oct. 20 column.) Mental-health experts view it as a form of obsessive-compulsive disorder. It's also seen in people with dementia, depression, attention-deficit disorder and brain injury, and after major life losses. As many as one in 50 Americans may fit the criteria.