Pica is a psychological disorder characterized by an appetite for substances that are largely non-nutritive, such as ice (pagophagia); hair (trichophagia); paper (xylophagia); drywall or paint; sharp objects (acuphagia); metal (metallophagia); stones (lithophagia) or soil (geophagia); glass (hyalophagia); feces (coprophagia); and chalk.

Pica is most commonly seen in pregnant women, small children, and persons with developmental disabilities such as autism. Children eating painted plaster containing lead may suffer brain damage from lead poisoning.

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