--   Developmental delays can be a cause of pica. In mentally disable patient, pica is caused because the individual is unable to differentiate between food and nonfood 

stuff(Staebler  K,  Helbing  E,  Rosenbach  C,  Renneberg  B. , 2010)

--   Basically, pica   is   often   observed   in   patients   with autism  and  mentally  disabled  people,  as  they  make them    detached    from    their    surroundings    and  develop   their   own   alone   world.   They   do   not participate in social groups and other activities, and often   spend their   time   in   doing   some   specific behaviours, one of them  is  kept  busy  in  eating  non-nutritive   or   inedible   material,   which   give   them satisfaction.  Various  researches  reported  that  60-66%  people  with  autism  often  develop  pica,  which show the intense relationship in such disorders(Dr Harender Singh,2015).

--     There were 3 cases of pica was reported - 2 impulse control disorder and 1 Obsessive Compulsive Disorder (Gundogar, Demir and Eren,2003)

--     Another fact regarding this disorder is that a large amount of negative   behaviour was   found   in   patients   with  a combination  of  pica  and  autism, when the comparison  made  between  groupings  with  single disorders.

--     This  concluding  statement  was  given  by  researchers  studying  on  adults  and  their  degree  to  which  autism  and  intellectual  disabilities  combined with  pica  in  them,  and  the  result  showed  that  they  have a lack of social skills. This study was published  in  the  month  of  October  2012  issued  in  The  Journal  of  Developmental  and  Physical  Disorders,  and  the results    claimed    that    adults    having    intellectual disabilities     and/or     with   Autism Spectrum Disorder(ASD) are  frequently observed   at   risk   for   rising   additional   forms   of  psychopathology    and/or    challenging    behaviours, including pica. 

·         It is not known exactly why pica is more common in pregnant women, but there is a theorized connection with iron deficiency according to the Journal of the American Dietetic Association. A microbiologist, Caroline Ndulie, said that eating non-food substances could interfere with the absorption of the nutrients of healthy food substances and thereby caused a deficiency. (Anne Effiong, 2013) said that the causes of pica in pregnancy is not exactly known, but medical and health indicators liken it to an iron or calcium deficiency.

·         A gynaecologist, Stanley Agboola, said that pica in pregnancy is an eating disorder where there is a craving for mostly non-food substances with little or no nutritional value. The most common substances that are craved by pregnant women who have pica are clay, laundry starch and dirt. This is due to malnutrition and their bodies' craving specific nutrients need to support and maintain pregnancy (Ortega, S., de Portela, C. & López, L.B. ,2004).

The subjects' blood iron levels were assessed during their pregnancies and delivery. The maternal iron status indicators of those who reported Pica behaviour showed significantly lower levels of iron relative to the group of subjects who did not report Pica behaviour(Lumish, Cooper & Guillet, 2014). 

·         Sometimes pica is embedded in fertility rituals, as with East African women, who eat soil before, during, and after pregnancy because they believe in the soil's magical potential to ensure future offspring.

·         In 2000, a workshop on pica organized by the Agency for Toxic Substances and Disease Registry decided that pica is not abnormal behaviour.The panel may also have been influenced by the work of researcher and social worker Kevin Grigsby. Grigsby studied black women in central Georgia who eat dirt, and he concluded that the phenomenon is a “culture-bound syndrome.” In other words, it’s a cultural practice, not a psychiatric illness.

Grigsby is among scientists who believe pica is as ancient as the human race and practiced by cultures across the globe, often as a folk remedy for the cravings and side effects of pregnancy. From Australia to Africa, the Middle East to Mississippi, there are people, particularly women, who believe the minerals found in dirt can enhance fertility, supplement their diets and help with the nausea common in the first trimester. 

(Valori Berends, MS, BCBA, Amber Persons, BCaBA and Amanda Teweleit, 2014)