Pica

Pica is the recurrent craving or consumption of nonnutritive items. The name was reportedly introduced in the 6th century by Aetius of Amida, a Byzantine physician, in reference to the magpie—pica pica—known for its propensity to gather all sorts of [Page 516]objects, albeit to build its nest not to consume as food. The practice has long been documented in the medical literature from Hippocrates and Galen in Antiquity, to Ambroise Paré and Jean Liebault in the 16th century, and throughout the 18th and 19th centuries when developing modern medicine turned its attention to European peasants and enslaved or subjugated populations in the Americas and Africa. Along the centuries, several other terms have been used to describe pica: malacia, cachexia africana, or mal d'estomac. This entry presents the major dimensions of the practice, including the products consumed, the scope of the phenomenon, the categories of people known to engage in pica, and the causes and consequences of the behavior.

Items consumed by pica patients constitute a long and diverse list. Soil or clay (geophagia), raw starch (amylophagia), feces (coprophagia), ice and freezer frost (pagophagia), paint chips (plumbophagia), wood, bark, and twigs (lignophagia), cigarette butts (tobaccophagia), and hair (trichophagia) are the most commonly noted in the literature. Ingestion of other soft (paper products, soap, fabric, clothing, and ashes) and hard nonorganic products (nails, bolts, coins, paper clips, crayons, and plastic items) has also been documented.

In most circumstances, pica is considered an eating disorder and is most commonly observed in individuals with developmental disabilities. However, geophagy, the consumption of soil, is culturally sanctioned in many societies, including the United States, and is mostly practiced by pregnant women and young children. Geophagy is found around the world with incidences varying from the very rare in northern Europe, to 5% in Tanzania, to more than 50% of pregnant women in Kenya, Ghana, and India. In the United States, rates have ranged from 14% to more than 50% among African American mothers, the most likely consumers of earth. In 2001, the Agency for Toxic Substances and Disease Registry of the Centers for Disease Control and Prevention estimated that 33% of American children ingest more than 10 grams of soil 1 or 2 days a year. Rates tend to be much higher in other regions of the world, between 29% and 75%.

Geophagy has been thought to help with nutrient supplementation (especially iron and calcium) during pregnancy and food shortages, with the adsorption of toxins in cases of poisoning, and with the relief of gastrointestinal discomfort. It was also thought to act against hunger by filling the stomach, to fulfill religious functions, especially in Central America, or to provide psychological comfort. However, recent research has challenged most of these explanations and has retained the detoxification hypothesis as the most likely. Still, researchers point to the relevance of integrating the biological, physical, cultural, and symbolic dimensions of geophagy to adequately understanding the behavior.

The situation is quite different for other forms of pica. An eating disorder, it is frequently observed in individuals with developmental difficulties such as autism, severe intellectual disability, and Prader–Willi syndrome, a genetic disorder associated with compulsive eating. The prevalence of pica within this population in the United States ranges from 9% to 25%. As it is the case for geophagy, the etiology of pica is difficult to establish. Nutritional factors such as anemia; environmental factors such as stress, poverty, or limited human interaction; sensory factors (pleasure generated by the smell, texture, or taste of ingested material), as well a variety of mental health factors from depression to schizophrenia have been associated with pica behavior.

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