Anytime paper and psychology intersect, you know I'm going to get excited!
According to the DSM-IV-TR, the diagnostic manual of psychiatry and clinical psychology, pica (diagnosis #307.52), is the "consumption of nonfood items, including dirt, clay, starch, ice, cloth, and so forth. Transient pica is very common in normal children, and may also be seen in about one-quarter of severely retarded patients. Pica may be seen in up to a third or more of pregnant women; it may also be endemic in certain culturally isolated groups, but is for the most part rare in otherwise normal adults."
Note especially this part: Transient pica is very common in normal children. Also, for someone to actually have a case of pica, the following DSM criteria need to be met:
- Persistent eating of non-nutritive substances for a period of at least 1 month.
- The eating of non-nutritive substances is inappropriate to the developmental level.
- The eating behavior is not part of a culturally sanctioned practice.
- If the eating behavior occurs exclusively during the course of another mental disorder (e.g., Mental Retardation, Pervasive Developmental Disorder, Schizophrenia), it is sufficiently severe to warrant independent clinical attention.
I think this question about pica is a good question because it relates to many things that are fun to think about: the culture of food, the definition of abnormal behavior in light of cultural expectations for behavior, and also a relatively new field in behavioral studies called zoopharmacognosy [Zoh-o-farm-uh-cog-nose-ee is how I say it].
Michael Huffman, a primatologist I would love to meet some day, perhaps at the Kyoto University of Japan in January when I'm in Kyoto, is one of the founders of the field. Zoopharmacognosy is basically the study of herbal medicinal use among animals. Primatologists like Huffman have discovered that monkeys and apes ingest substances that are not food because they have beneficial properties. These include charcoal, mud, the bitter pith of trees and various other things that are not normally eaten, including in the case of woolly spider monkeys and lemurs — plants that affect fertility.
Here's a brief synopsis of some non-foods that animals eat for health reasons:
- Aspilia plant leaves - chimpanzees - rids intestinal parasites
- Vernonia bush pith - chimpanzees - helps upset stomach
- fruit from the 'Monkey Ear' plant - woolly spider monkey - increased fertility
- leaves of Apulia leiocarpa & Platypodium elegans - woolly spider monkey - decreased fertility
- Boraginaceae trees - elephants - induce labor
- clay - spider monkeys - diarrhea treatment
- charcoal - colobus monkeys - counteract toxins in a highly nutritious plant
The condition pica, even as defined by the DSM, may not be inherently abnormal or 'crazy' after all. Perhaps the child who eats paper senses a dietary deficiency in fiber. And maybe the pregnant woman who craves dirt or clay instinctively wants to cleanse toxins from her body to keep the fetus healthy. However, there is no doubt in my mind that some forms of pica — such as a French man who ingested $650 worth of coins — are clearly abnormal and dangerous to one's health. Pica is just one example of a healthy behavior that when taken to the extreme, is anything but.
For further reading:
Really Wild Remedies
Geophagy: Soil Consumption
By Watching What Animals Eat, Experts May Find New Medicines for People
Bite the Bullet: A man who ate bullets