“They grew up in this difficult environment and naturally came to resent it,” Dr. Frost said. “But at the same time, these are your parents and you have to not only respect and love but take care of them. What happens when they get old?”

NOT surprisingly, there are a number of online support groups and blogs devoted to children of hoarders, including Hoarder’s Son and Behind the Door. The most popular, Children of Hoarders, maintains an online forum where members trade strategies for helping parents, discuss issues like “doorbell dread” (more on that later) and share stories. One account, posted by a woman named Tracy Schroeder, details in emotionally raw terms her mother’s death and the subsequent cleanup of the family home in Clovis, N.M., which was filled with magazines, craft supplies and dog feces.

“The COH Web site was my saving grace,” Ms. Schroeder, 42, said. “Nobody understands the weirdness of growing up this way unless they go through it.”

In high school, Ms. Schroeder said, she was a cheerleader and president of her class, but she lived in constant fear that “someone would see our house.” After her parents divorced, she strategically arranged visits with friends when she was spending weekends with her father. The college she attended was 20 minutes from her mother’s house, but she rarely visited, she said, because “I wouldn’t want to stay there, and that would cause fights.”

Her reluctance to visit became a moot point when her mother eventually stopped letting her in. By the time she died, in 2006, Ms. Schroeder said, “I hadn’t been in the house for eight or nine years.”

She added, mournfully: “She wouldn’t let you help — that’s what’s so frustrating. She would cut you out if you brought it up.”