The exact causes of pica are not known. However, researchers believe that certain conditions and situations may contribute to the development of this eating disorder. These include:

• Cultural factors. In some places (e.g., portions of southern Africa), the consumption of earth substances (geophagia), such as certain types of soil or soil and herbal preparations, is sometimes practiced.
  
  
• Mental health disorders. Pica may co-exist with other types of mental health disorders including obsessive-compulsive disorder (OCD), schizophrenia (as a result of delusional beliefs) and Kleine-Levin syndrome (a rare condition characterized by episodes of excessive sleep in addition to behavioral and/or cognitive disturbances including excessive food consumption, sexual disinhibition and hallucinations).
  
  It is also frequently reported in individuals with autism and mental retardation. Though to some degree this may be due to the inability of these patients to differentiate between food and nonfood items, it is thought that it may be more commonly related to a form of self-stimulation.
  
  
• Nutritional deficiencies and/or malnutrition. Pica has been reported in individuals with deficiencies in minerals such as iron, calcium and zinc as well as other nutrients and vitamins (e.g., thiamine, niacin, vitamins C and D). However, it is unclear whether pica is related to an attempt to correct these deficiencies.  Poverty may be the cause of malnutrition in some people. Children who are abused or neglected may also be malnourished.
  
  
• Pregnancy. The craving and consumption of nonfood items associated with pica –   especially dirt, clay and laundry starch – may sometimes occur in pregnant women. Iron deficiency during pregnancy appears to be related to excessive eating of ice. However, pica that develops during pregnancy usually resolves on its own once the mother gives birth.
  
  
• History of dieting and/or other eating disorders. Individuals who undergo prolonged diets may attempt to ease hunger by eating nonfood substances to achieve a feeling of fullness. It is possible, although uncommon, for individuals with other eating disorders such as anorexia and bulimia to develop pica due to the compulsive nature of these illnesses as well as the malnutrition that may result from them.