When pica is not caused by an iron deficiency, it is often "a disturbance in the thought process," according to Dr. G. Richard Locke, a gastrologist and motility expert from the Mayo Clinic.
A non-food material could become microscopic and toxins might be absorbed into the system, but most materials small enough to work their way from top to bottom eventually pass.
"It has to get through the intestine," Locke said in an interview about Edwards' addiction to sofa foam. He has treated patients who have swallowed coins and hair balls, among other things.
The digestive tract is "one long tube from the mouth to the bottom," he said. "It's in our body, but not actually in our body. It protects us."
Treatment for these eating behaviors includes first addressing missing nutrients or exposure to toxins like lead. Then, specialists address behavioral and family issues.
"Using behavioral replacement therapy to treat addiction is a clinically effective part of treatment," said psychologist Dow. "This means we help the addict to find healthy habits -- like walking an hour a day or a daily meeting -- to replace the unhealthy addiction like smoking or even eating deodorant."
As for Nicole, at the urging of her boyfriend, she has tried to cut back on eating deodorant. She replaces her craving with eating almonds, but she has not been able fully to give it up.
"It's really soft," she says. "It feels like it melts in my mouth. Deodorant really has a unique taste of its own."
But Dow said that maintaining long-term sobriety is difficult. "It's not easy to give up an addiction that's become part of your daily life."