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.

About drmarkgriffiths

Professor MARK GRIFFITHS, BSc, PhD, CPsychol, PGDipHE, FBPsS, FRSA, AcSS. Dr. Mark Griffiths is a Chartered Psychologist and Distinguished Professor of Behavioural Addiction at the Nottingham Trent University, and Director of the International Gaming Research Unit. He is internationally known for his work into gambling and gaming addictions and has won many awards including the American 1994 John Rosecrance Research Prize for “outstanding scholarly contributions to the field of gambling research”, the 1998 European CELEJ Prize for best paper on gambling, the 2003 Canadian International Excellence Award for “outstanding contributions to the prevention of problem gambling and the practice of responsible gambling” and a North American 2006 Lifetime Achievement Award For Contributions To The Field Of Youth Gambling “in recognition of his dedication, leadership, and pioneering contributions to the field of youth gambling”. In 2013, he was given the Lifetime Research Award from the US National Council on Problem Gambling. He has published over 800 research papers, five books, over 150 book chapters, and over 1500 other articles. He has served on numerous national and international committees (e.g. BPS Council, BPS Social Psychology Section, Society for the Study of Gambling, Gamblers Anonymous General Services Board, National Council on Gambling etc.) and is a former National Chair of Gamcare. He also does a lot of freelance journalism and has appeared on over 3500 radio and television programmes since 1988. In 2004 he was awarded the Joseph Lister Prize for Social Sciences by the British Association for the Advancement of Science for being one of the UK’s “outstanding scientific communicators”. His awards also include the 2006 Excellence in the Teaching of Psychology Award by the British Psychological Society and the British Psychological Society Fellowship Award for “exceptional contributions to psychology”.

Posted on March 9, 2012, in Compulsion, Eating addiction, Eating disorders, Obsession, Obsessive-Compulsive Disorder, Pica, Psychiatry, Psychology and tagged , , , , , , , , . Bookmark the permalink. 4 Comments.

  1. Stephen Woodward

    Hi there,

    [For those who don’t know I studied under Mark Griffiths at University of Plymouth in 1992 as a psychology undergraduate.]

    What I wanted to comment was an issue relating to the nutritional value of substances that are eaten and their calorific value. As someone who has read public health and health promotion this will probably appal many who are working in the area but there is an underlying assumption that everything that an individual eats needs to be of some nutritional value. What may be worth considering is that evolution may have selected those who can go without food for long periods and that some non-nourishing substances may be of benefit to have in our intestines or other parts of our systems.

    Could a nutrition rich diet be one of the main reasons for some forms of cancer that are on the rise at present? Could eating non-nutritional items assist with cleaning out our systems and removing toxic substances? Could common grasses have served a similar function but have been removed from our diet?

    I realise that inadequately nutritional meals are a significant risk to human development and it will be a long time before there is a lobby stating that pica shouldn’t be classed as a disorder of eating, However, there could be a means of raising questions regarding eating disorders and how they function socially and politically. Is this a strong enough argument for a dietician to get involved?

    It would be interesting to examine what may be classed as a Marxist perspective on dietry requirements and how well we understand our nutritional needs. Does the average western nation want to define health in a fashion that will enable their citizens to have a productive day at work every day? Do they want them to have a diet which will enable them to do this? Really the answer is yes, despite the fact that there could have been evolutionary or health advantages to having a poor diet for certain periods of time.

    I’d hope that I can add some form of sensible disclaimer to this – there could be people who may wish to change their diets over paranoia about bowel cancers. I’m not stating this is definitely linked, however, there is some food for thought here. Could oncologists or dieticians comment?

    Stephen Woodward.

    • Hi Stephen

      Lovely to hear from you after all these years. Some really excellent comments. I was going to say “food for thought” but maybe it should be “non-food for thought”.


  2. Stephen Woodward


    It’s good to see you’re so active in the blogging sphere and putting up well referenced blogs – unlike me. I meant to state, that I think that there are some instances of non-nutritional items being anecdotally referred to as having minor health benefits, for instance a burnt match being a good means of settling an unsettled stomach. Has someone who repeatedly eats coal experiencing some form of jackpot linked addiction pattern, if eating a match or carbon has worked for them particularly well on one occasion in the past?

    I would have a concern that should there be some indication that eating non-nutritional items could have fringe health benefits then there would be a market for them and the diagnostic category would change quite significantly. [I did mention calorific value above – an appetite suppressant that would fill your stomach, leave you feeling full, and also has potential to clean out your intestines reducing the chances of bowel cancer would have a value to a great many people, unbalanced diets are linked quite significantly to weight gain and this may be a boom area, although at this point, this is a long way off until nutritional messages are more fully absorbed by the public. ]

  3. Hello, I am a 48 year old women and when my mother was pregnant with me she ate plaster from the wall. She ate so much that she had to put a large frying pan over to cover up the hole. What kind of side effects could there be for me, since I had tons of unexplained health issues. I would love to hear from someone who can help me.

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