Pica boom? A beginner’s guide to pica

Pica is an eating disorder that has been documented in the psychological literature for hundreds of years and refers to a behaviour in which individuals eat non-nutritive items or substances (such as coal, hair and wood). The American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) defines pica as “the persistent eating of nonnutritive substances for a period of at least one month, without an association with an aversion to food”. Therefore, one-off instances of eating non-nutritious items would not constitute pica. Children who occasionally eat items like crayons are rarely diagnosed as having pica. Pica comes from a Latin word for the magpie bird (known for its strange eating behaviours).

The prevalence rates of pica depend on which patient populations have been studied. Prevalence estimates are also skewed by the fact that many people suffering from pica are embarrassed about the behaviour and may not tell anyone and/or seek medial treatment. However, it is well established that pica is more prevalent in children, pregnant women, adults from lower socioeconomic classes, and children with developmental disabilities (such as autism). The incidence of pica is also higher amongst those suffering from family-related stress. Although pica can be a symptom of anaemia (i.e., iron deficiency) and other chemical imbalances, research has shown it is actually more common among those who have normal iron levels.

Prevalence rates of pica have range anywhere between 0.02% and 74% depending on the study and population studied. For instance, studies have reported pica prevalence rates of:

• 0.02% in Danish pregnant women
• 8% in US black pregnant women (pagophagia)
• 9% in Saudi Arabian pregnant women
• 26.5% in Tanzanian pregnant women (geophagia)
• 31% of Californian Mexican pregnant women
• 44% of Mexican pregnant women
• 50% of Nigerian pregnant women
• 74% in Kenyan pregnant women
• 44% in French anaemic patients (vs. 9% matched controls)
• 64% in Turkish anaemic patients (vs. 17% controls)
• 22%-26% in mentally retarded adults
• 34% in sickle cell disease patients

The Danish figure from a study led by Dr Tina Mikkelsen (University of Southern Denmark) is likely to be the most accurate as it was carried out on a sample of 100,000 pregnant Danish women and only 14 of the total sample reported that they had pica. The authors concluded that in privileged populations, pica is more a myth than a reality.

Despite increased research in the area, there has been no definitive explanation as to why some people consume such substances as hair (trichophagia), ice (pagophagia – which I briefly examined in a previous blog), soil/clay (geophagia), wood (xylophagia), stones (lithophagia), glass (hyalophagia), plumbophagia (lead paint chips), or laundry (uncooked) starch (amylophagia). Dr. Ella Lacey (Southern Illinois University) also listed many other non-food substances that pica sufferers may eat that don’t have specific names such as those people who eat paper, balloons, grass, soap, cotton wool, and cigarette butts. Pica is a widespread practice throughout Africa and India. It has also been reported in Australia, Canada, Israel, Iran, Uganda, Jamaica and various European countries. A recent review on pica led by Dr Sera Young (University of California, USA) noted that geophagia is the most common type of pica described in the psychological and medical literature. They also noted that:

• Geophagics frequently eat other non-food stuffs.
• Those who eat more manufactured substances say they use them as a replacement for earth, either because the desired soil is unavailable or socially unacceptable
• Bar the eating of ice, most pica substances are absorptive in the dry state and all easily absorb moisture.
• Pica substances are typically craved with great intensity or ‘‘devouring passion’’

A variety of conditions are known to cause some types of pica including mineral deficiencies, hookworm infection (parasitic infection in the small intestine), coeliac disease (an autoimmune disorder of the small intestine) and Kleine-Levin Syndrome (also known as Sleeping Beauty Syndrome, a neurological disorder characterized by recurring periods of excessive amounts of sleeping and eating). Interestingly, there are culture-specific cases where pica is not related to psychopathological disorders or deficiencies. For instance, black women in Georgia (USA) are known to eat kaolin (white dirt that is actually a clay mineral) – a so-called “culture-bound syndrome” (i.e., a recognizable combination of psychiatric and somatic symptoms that are only within a specific culture or society).

Some pica type disorders may be part of a wider psychiatric condition (such as schizophrenia) and/or may be part of a sexual paraphilia such as the small numbers of people who engage in coprophagia (eating faces) as part of coprophilia and people who engage in urophagia (drinking urine) as part of urophilia. If the primary focus for eating the item or substance was sexual, it would be more likely diagnosed as a sexual paraphila rather than pica. However, many of those with pica claim to love the taste, texture and/or smell of the things they eat. Some studies have suggested an association between pica and addictive behaviors. Others suggest pica is on the obsessive-compulsive disorder (OCD) spectrum of diseases. For instance, a study based on pica case studies by Dr Dan Stein and colleagues (a the University of Stellenbosch, South Africa) came to the conclusion that (based on their case studies), pica may be a symptom of OCD, and that pica may be phenomenologically reminiscent of an impulse control disorder.

For many people, pica is not dangerous but for some there may be complications including (i) parasitic infections (such as geophagics eating soil or copraphagics eating faeces), (ii) internal bodily obstruction (e.g., such as tricophagics getting hair stuck in their intestines), (iii) toxic reactions (e.g., such as autistic children getting lead poisoning from eating painted plaster), (iv) excessive caloric intake (such as that occurring with starch cravings), (v) dental injuries and infections, and (vi) nutritional deficiencies.

As Dr. Lacey concluded: “Pica appears to be a complex behavior that requires deliberate study rather than application of ex post facto single cause theories. Although such theories may motivate any given study of pica, it should be apparent that any single cause model will likely offer only a limited explanation of such diverse practices as have been described in the literature through case reports,’ research studies, and literature ‘reviews of various clinical and applied disciplines”

Dr Mark Griffiths, Professor of Gambling Studies, International Gaming Research Unit, Nottingham Trent University, Nottingham, UK

Further reading

al-Kanhal, M.A., & Bani, I.A. (1995). Food habits during pregnancy among Saudi women. International Journal for Vitamin and Nutrition Research, 65, 206-210.

Ashworth, M., Hirdes, J.P. & Martin, L. (2008). The social and recreational characteristics of adults with intellectual disability and pica living in institutions. Research in Developmental Disabilities, 30, 512-520.

Danford, D.E. & Huber, A.M. (1982). Pica among mentally retarded adults. American Journal of Mental Deficiency, 87, 141-146.

Edwards, C.H., Johnson, A.A., Knight, E.M., Oyemade, U.J. et al (1994). Pica in an urban environment. Journal of Nutrition, 124(6 Suppl): 954S-962S.

Kettaneh, A., Eclache, V., Fain, O., Sontag, C., Uzan, M. Carbillon, Stirnemann, J. & Thomas, M. (2005). Pica and food craving in patients with iron-deficiency anemia: A case-control study in France. American Journal of Medicine, 118, 185-188

Lacey, E. (1990). Broadening the perspective of pica: Literature review. Public Health Reports, 105, 29-35.

López, L.B., Ortega Soler, C.R. & de Portela, M.L. (2004). Pica during pregnancy: A frequently underestimated problem. Archivos latinoamericanos de nutricion, 54, 17-24.

Mikkelson, T.B., Andersen, A.M. & Olsen, S.F. (2006). Pica in pregnancy in a privileged population: myth or reality. Acta Obstetricia et Gynecologica Scandinavica, 85, 1265-1266.

Ngozi, P.O. (2008). Pica practices of pregnant women in Nairobi, Kenya. East African Medical Journal, 85(2), 72-79.

Nyaruhucha, C.N. (2009). Food cravings, aversions and pica among pregnant women in Dar es Salaam, Tanzania. Tanzania Journal of Health Research, 11(1), 29–34.

Rose, E.A., Porcerelli, J.H, & Anne Neale, A.V. (2000). Pica: Common but commonly missed. Journal of the American Board of Family Practice, 13, 353-358.

Simpson, E., Mull, J.D., Longley, E., & East, J. (2000). Pica during pregnancy in low-income women born in Mexico. Western Journal of Medicine, 173, 20-24.

Smulian, J.C., Motiwala, S. & Sigman, R.K. (1995). Pica in a rural obstetric population. Southern Medical Journal, 88, 1236–1240.

Stein, D.J., Bouwer, C. & van Heerden, B. (1996). Pica and the obsessive- compulsive spectrum disorders. South African Medical Journal, 86, 1586-1592.

Young, S.L., Wilson, M.J., Miller, D., & Hillier, S. (2008). Toward a comprehensive approach to the collection and analysis of pica substances, with emphasis on geophagic materials. PLoS One, 3(9), e3147.