PICA is the compulsive eating of anything. It probably occurs in more than half of patients with iron deficiency. They usually conceal the problem from the physician, even when it is causing emotional anguish. It is not restricted to disadvantaged people.
Pica has had a play in the papers and in some of the throw-away journals, with a notably happy result. One kind of pica, the compulsive eating of flaked old paint by children in flaking old tenements causes lead poisoning. Laws have now forbidden the use of lead-based interior paints. There are other well-known kinds of pica. The eating of clay by black women in the South has the legitimacy of folk medicine and social custom, but it also has the quality of compulsive behavior. Clay eating has spread to the cities, where the clay can sometimes be bought in supermarkets. Sometimes, it is mailed from home. Laundry starch
Crosby WH. Pica. JAMA. 1976;235(25):2765. doi:10.1001/jama.1976.03260510055032