The causes of pica eating disorder (not technically an eating disorder, but has to do with disordered eating) are unknown. However, psychological functioning can play a role, malnutrition may be a factor and socioeconomic status may also influence the development of pica disorder. Cultural influences may also influence the development of pica eating disorder.
Developmental Disabilities
Pica eating disorder is often seen in those with lower psychological functioning, as in pervasive developmental disorder, autism, mental retardation and other developmental disorders or brain abnormalities. Theories suggest that persons with developmental disabilities cannot tell the difference between food items and non-food items, and will therefore eat non-food items when they are hungry if food is not available. However, scientific studies have failed to validate this theory.
Pica eating disorder has been documented to occur in up to 25% of mentally retarded patients who are institutionalized and occurs in up to 60% of those with autism, at least according to one study. (Garfunkel PE: Feeding and eating disorders of infancy and early childhood, in Comprehensive Textbook of Psychiatry, edited by Kaplan HI, Sadock BJ. Baltimore, MD, Williams & Wilkins, 1995, pp. 2321–2324.)
Malnutrition or Nutritional Deficiencies
Some scientists theorize that pica disorder could be a result of the lack of nutrients or minerals in a person's diet. So if iron is low in the body, the person will "crave" iron substances. Similarly, if zinc is lacking, the person will be drawn to substances that contain zinc. In pregnant women, a population that can engage in pica behaviors, this seems to be true. Pregnant women have been known to seek out iron-containing, non-food items. When treated for iron-deficiency anemia, however, pregnant women stop eating iron rich, non-nutritive substances. This is also true for other populations ... at least in some cases ... where the deficiency is identified, treatment ensues to correct the deficiency, and the pica behavior disappears. This is not true for all cases, however.
Socioeconomic Status and the Causes of Pica Eating Disorder
Studies suggest that in lower socioeconomic populations, pica disorder is more prevalent. Why? Probably for a couple of reasons. First, in lower socioeconomic communities, parental involvement tends to be lacking. Parents teach children that eating non-food items is inappropriate. Without parent involvement and attention when children do try eating things like dirt and sand and chalk, without parents to say, "Ewww, yucky. Dirt is not for eating," children may continue to eat the non-nutritive substances.
Hunger may also play a role as one of the causes of pica eating disorder. In lower socioeconomic populations, food may be scarce. Hunger may dictate that a child eats non-nutritive substances in an attempt to satisfy hunger. Combined with lack of parental involvement, a pica disorder could develop.
Cultural Factors influencing Causes of Pica Eating Disorder
In some cultures, eating non-nutritive substances is included as part of the cultural rituals. In other cultures, the society believes there are magical qualities or healing qualities to some non-nutritive substances. Typically these substances are clay and soil. Pica is often found in India, southern Africa and western Kenya. Soil, for instance, is sold in Uganda for the purpose of eating.
