Contrasting Pica Behavior for Individuals with ASD and IDD Against Presentation in the General Population Part I

Contrasting Pica Behavior for Individuals with ASD and IDD Against Presentation in the General Population – Part I

By Janice Goldschmidt, MS, RD, LDN
Director of Nutrition Services
Community Support Services, Inc.

(This is Part I of a 3 part series on the named topic. Part II will continue in the January 2019 E-Newsletter. And Part III will appear in the February 2019 E-Newsletter.)

This analysis is intended to introduce healthcare professionals to the patterns of pica behavior, diagnosis and treatment for those with autism spectrum disorder (ASD) and other intellectual and developmental disabilities (IDD). In so doing, it will contrast this behavior with what is understood regarding pica presentation among the general population. Pica is relatively well defined as an eating disorder, but for those with ASD and IDD this condition is manifested in distinctive patterns. It is important that healthcare professionals working within the realm of disordered eating have a measured understanding of the clinical presentation of this behavior for those with ASD and IDD and appreciate how it differs from pica in the general population.

Pica[1]is formally defined as the consumption of abnormal or unusual nonfood substances. Traditionally, pica was inclusive of various non-nutritive items that no longer fit within the diagnostic understanding of the condition, including consumption of ice and scavenging for food. Pica behavior is manifested in both genders and across the lifespan.1

ASD, a neurobiological condition with no clear biologic marker, is diagnosed through assessment of deficits in communication and social development as well as behavior rigidity.2There is a pronounced diversity of presentation and a tremendous range of abilities and impairment.  Autism falls under the larger umbrella of developmental disability (DD), which is defined by severe impairments in cognitive and/or physical functioning with onset before the age of 22.[2] Autism also has a large overlap, or comorbidity, with intellectual disability (ID). Because ASD and intellectual/developmental disability (IDD) are diagnostically related, research addressing one of these cohorts is often applicable to at least portions of the other.

Pica in the General Population 

For nutrition professionals, pica is most commonly associated with pregnant women as a sporadic behaviorduring the gestation period or post-natal during breastfeeding.3,4 Pica during pregnancy is idiopathic though hypothesized as a response to nausea and/or vomiting as well as a physiological response to varied nutritional deficiencies.5 Among pregnant women geophagia — the consumption of soil or clay — is the most prevalent form of presentation.3,4See Table 1 for a listing of the most common categories of pica behavior.

Pica is also demonstrated in typically developing children, possibly as a form of tactile input or as a means of exploration. For this cohort, pica behavior is typically extinguished naturally during the progressive aging process.6Childhood prevalence for pica has been estimated between 10%-32% for children under age 6 though this figure refers to occasional episodes, rather than ongoing behavior. Children under the age of two are believed to have the highest prevalence.7

Pica has also been associated with specific medical conditions, often as a response to treatment protocols.  Patients undergoing dialysis in the treatment of kidney disease have sometimes presented with pagophagia, amylophagia, and geophagia.8 Likewise, sickle cell anemia has been known to promote the ingestion of sponge or foam rubber in children and adolescents.9,10 Pica is also documented among individuals with dementia.11

In a variety of cultures and geographical regions, presentation of pica is acknowledged as a sanctioned behavior though it often coincides with pregnancy-induced pica.12-14  Culturally organized pica has been assessed in diverse contexts including rural life in India,12fertility rituals among women in East Africa,13and famine-induced pica in Europe.14 Pica is also considered medicinal in certain regions, including Peru and Bolivia.15

Overall rates of pica among the general population are not well understood, nor is there sufficient depth to studies of prevalence as they typically lack detail related to persistence, duration, and relationship with socio-cultural traditions.6 Further, as pica is generally perceived as a socially undesirable behavior, self-reports are likely to skew the clinical understanding.16 Still, the Agency of Healthcare Research and Quality reported that between 1999 and 2009 there was a 93% increase in cases of pica, the largest rise for any category of eating disorder.17

Pica in the ASD and IDD Population 

In comparison with the rather narrow definition of pica in the general population, the characterization of pica for those with ASD and IDD is much more variable and often skews significantly away from the diagnostic criteria.18 That is, individuals presenting with symptoms of pica in the general population display discriminate behavior, or specific consumption of one item or class of substance (e.g., clay or starch). Among those with ASD and IDD, indiscriminate or generalized pica is more often demonstrated.11 While some of these individuals have preferred items for ingestion, others are scavengers, randomly choosing items, or are simply opportunistic (see Table 2 for comparison of pica in the general population and on the autism spectrum).

The published rates of pica in the ASD and IDD literature are highly variable, though the highest rates are identified in institutionalized settings. A record review of 70 hospital patients with ASDfound that 60% of the subjects had displayed pica behavior at some point. This was contrasted with a comparable groups of individuals with Down syndrome where pica was recorded at a prevalence of 4%.19

One review found rates of pica in institutional contexts within a range of 5.7% – 25.8%. However, the researcher noted so many differing methodologies and definitions of pica that overall patterns were difficult to discern.20,21 Studies addressing prevalence rates for individuals living in community-based settings have documented far lower rates of pica ranging from 0.2% to 4.1%.20

Cigarette pica is reported as the most commonly ingested item for individuals with ASD and IDD,22-26despite relatively low rates of documented nicotine use.27 Published research of items ingested by those with ASD and IDD are tremendously diverse (see Table 3) Studies have noted the consumption of items that would be found naturally in many residential contexts (e.g. buttons) while others are contextual or specialized (e.g. holiday ornaments). Some of the published items clearly have the potential to be lethal (e.g., broken glass, dead animals).

Despite widespread documentation of this condition for those with ASD and IDD, in the absence of overt physiological signsmost healthcare professionals would likely not probe staff regarding ingestion patterns.28 One clinical treatment plan for institutionalized individuals with ASD and IDD has been proposed.29 Williams and McAdam advocate for screening; individualized assessment and treatment programs; pica-safe environments; staff training; as well as establishment of special contexts for safety. The authors also write that those individuals who display high frequency pica likely need to have limited access to the community.29

Acknowledgements

This analysis was originally undertaken as an independent study during my graduate studies at the University of Maryland – College Park.  Special thanks to Thomas Castonguay, PhD for guiding me during that research process and helping me find the appropriate focus for this paper.

[1]Pica comes from the Latin word for a bird renowned for eating almost anything, the magpie.

[2]Aside from ASD and ID, developmental disabilities is inclusive of a number of conditions including Cerebral Palsy as well as a range of neurogenetic, behavioral, metabolic and muscular disorders.