The term was drawn directly from the medieval Latin word for magpie, a bird subject to much folklore regarding its opportunistic feeding behaviors.

[4] According to the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5), pica as a standalone eating disorder must persist for more than one month at an age when eating such objects is considered developmentally inappropriate, not part of culturally sanctioned practice, and sufficiently severe to warrant clinical attention.

[5] In addition, it can cause surgical emergencies to address intestinal obstructions, as well as more subtle symptoms such as nutritional deficiencies and parasitosis.

[5][6] Pica is most commonly seen in pregnant women,[7] small children, and people who may have developmental disabilities such as autism.

Subtypes are characterized by the substance eaten:[12] This eating pattern should last at least one month to meet the time diagnostic criteria of pica.

Ingestion of kaolin (white clay) among African American women in the US state of Georgia shows the practice there to be a DSM-4 "culture-bound syndrome" and "not selectively associated with other psychopathology".

[33] Such practices may stem from purported health benefits, such as the ability of clay to absorb plant toxins and protect against toxic alkaloids and tannic acids.

The healthcare provider should test and monitor for infection if the patient has been eating contaminated soil or animal waste.

[20] The DSM-5 posits four criteria that must be met for a person to be diagnosed with pica:[3] In individuals with autism, schizophrenia, and certain physical disorders (such as Kleine–Levin syndrome), non-nutritive substances may be eaten.

[8] Geophagia is a form of pica in which the person consumes earthly substances such as clay, and is particularly prevalent to augment a mineral-deficient diet.

[49] Noteworthy is the fact that kaolin was consumed by West Africans enslaved in the Southeastern United States, particularly the Georgia belt, due to the antidiarrheal qualities in the treatment of dysentery and other abdominal ailments.

Kaolinite became the active ingredient in antidiarrheal drugs such as Kaopectate, although it was replaced by attapulgite in the 1980s and by bismuth subsalicylate starting in 2004.

Even today, what could be classified as pica behavior is a normative practice in some cultures as part of their beliefs, healing methods, or religious ceremonies.

[44] The Glore Psychiatric Museum in Saint Joseph, Missouri has a 1910 exhibit with "an imaginative starburst arrangement of 1,446 buttons, screws, bolts, and nails that were eaten by a patient who died unexpectedly.

"[52] Unlike in humans, pica in dogs or cats may be a sign of immune-mediated hemolytic anemia, especially when it involves eating substances such as tile grout, concrete dust, and sand.

Dogs exhibiting this form of pica should be tested for anemia with a complete blood count or at least hematocrit levels.

[53][54] Although several hypotheses have been proposed by experts to explain pica in animals, insufficient evidence exists to prove or disprove any of them.