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.
Causes: Although the etiology of pica is unknown, numerous hypotheses have been advanced to explain the phenomenon, ranging from psychosocial causes to causes of purely biochemical origin. Cultural, socioeconomic, organic, and psychodynamic factors have been implicated.