Functionally, these neurons are either motor (conducting impulses that will cause activity such as the contraction of muscles) or association (conducting impulses and permitting 'communication' between neurons within the central nervous system).
The scant research that has been done on the causes of pica suggests that the disorder is a specific appetite caused by mineral deficiency in many cases, such as iron deficiency, which sometimes is a result of celiac disease or hookworm infection.
Warning signs that a child may have pica include: 1  eating of nonfood items, despite efforts to restrict it, for a period of at least 1 month or longer. 2  the behavior is considered inappropriate for your child's age or developmental stage. 3  the behavior is not part of a cultural, ethnic, or religious practice.