Clinical Vignette
Patient: "Mr. D," 28-year-old man with mild intellectual disability (IQ 62), residing in a group home, referred after ingesting metal objects requiring surgical removal.
Chief Concern: Group home staff: "We found Mr. D swallowing coins, paper clips, and small screws from furniture. He's been to the ER twice for foreign body removal in 6 months. We've found him chewing on chalk and eating dirt from the garden."
History of Present Illness: Mr. D has a 5-year documented history of eating non-food substances. Substances ingested include: coins (pennies, nickels), paper clips, small screws, chalk, dirt/soil (geophagia), and paper. He does not display hunger when engaging in pica behavior and it does not occur exclusively at mealtimes. He has required 2 ER visits in 6 months for foreign body ingestion (one requiring endoscopic removal). Staff observe him seeking out these items deliberately: he removes screws from furniture, searches the garden for dirt, and collects coins from surfaces. He has been told repeatedly that these items are dangerous, but his understanding of the medical risk is limited by his intellectual disability. Nutritional evaluation: no iron, zinc, or other micronutrient deficiencies identified. His dietary intake of regular food is adequate.
Medical History: Mild intellectual disability (IQ 62). Two ER visits for foreign body ingestion. No iron or zinc deficiency.
Mental Status Exam: Cooperative. Limited verbal expression (consistent with mild ID). Understands concrete instructions. Affect cheerful. When asked why he eats coins, responds: 'I like how they feel.' No psychotic symptoms. No obsessive-compulsive features. Insight limited by intellectual disability.
Step 1: Pica DSM-5-TR Criteria
Criterion A: Persistent eating of non-nutritive, nonfood substances over a period of at least 1 month.
Five-year pattern of eating coins, paper clips, screws, chalk, dirt, and paper. Far exceeds 1-month minimum. MET.
Criterion B: The eating of non-nutritive, nonfood substances is inappropriate to the developmental level of the individual.
Mr. D is 28 years old. Even given his intellectual disability (mild, IQ 62), eating metal objects and dirt is inappropriate. His developmental level (approximately 8-10 years) exceeds the age at which mouthing/ingesting non-food items is developmentally expected. MET.
Criterion C: The eating behavior is not part of a culturally supported or socially normative practice.
No cultural practice of geophagia in his context. Eating coins and paper clips is not culturally sanctioned. MET.
Criterion D: If occurring in the context of another mental disorder or medical condition, it is sufficiently severe to warrant additional clinical attention.
Occurs in context of intellectual disability but is sufficiently severe (surgical foreign body removal, ER visits) to warrant independent diagnosis. MET.
Step 2: Clinical Context and Risk
| Risk Factor | Assessment | Intervention |
|---|---|---|
| GI obstruction | Metal objects (coins, screws, paper clips) can cause bowel obstruction or perforation | Environmental modification: remove accessible small metal objects |
| Heavy metal toxicity | Chronic coin ingestion → zinc and copper exposure | Lab monitoring: zinc, copper, lead levels |
| Dental damage | Chewing metal objects → enamel damage, tooth fracture | Dental assessment |
| Parasitic infection | Geophagia (dirt eating) → parasitic and bacterial exposure | Stool studies: ova and parasites |
| Nutritional deficiency | Iron and zinc deficiency can CAUSE or MAINTAIN pica (not present here) | Already assessed: no deficiency found |
Treatment Priority
Mr. D's pica poses immediate physical danger (GI obstruction, heavy metal toxicity). Environmental modification (removing access to dangerous objects) is the most urgent intervention, followed by behavioral treatment.
Diagnostic Formulation
Diagnostic Conclusion
Pica, in the Context of Intellectual Disability (F98.3 + F70): All 4 DSM-5-TR criteria met. Five-year duration. Substances: metal objects, chalk, dirt, paper. Medical complications: 2 surgical ER visits. No nutritional deficiency identified as a contributing factor. Treatment: (1) Environmental modification (restrict access to dangerous non-food items). (2) Applied Behavior Analysis (ABA) — discrimination training (food vs. non-food), reinforcement of appropriate eating. (3) Increased supervision during unstructured time. (4) Medical monitoring (heavy metals, GI imaging as indicated).
Teaching Points
- Pica can occur in individuals with intellectual disability, ASD, pregnancy, and in individuals with no comorbid condition. When it co-occurs with another condition, it is diagnosed separately only when its severity warrants independent clinical attention (Criterion D).
- Iron and zinc deficiency can both CAUSE and RESULT FROM pica. When nutritional deficiency is identified, supplementation may reduce or eliminate pica behavior. Mr. D's normal nutritional labs suggest his pica is not deficiency-driven, which affects the treatment approach.
- The developmental level criterion (Criterion B) is critical for distinguishing pica from normal mouthing behavior in infants and toddlers. Children under approximately 2 years routinely mouth and sometimes ingest non-food items as part of normal oral exploration. Pica should not be diagnosed before this developmental threshold.
- Applied Behavior Analysis (ABA) is the evidence-based behavioral treatment for pica in individuals with intellectual disability. Key techniques include discrimination training (teaching to differentiate food from non-food), differential reinforcement (rewarding appropriate eating, redirecting pica behavior), and systematic environmental management.
- Geophagia (earth/dirt eating) is the most common form of pica globally and is culturally practiced in some populations. DSM-5-TR requires that the behavior NOT be culturally sanctioned (Criterion C) for diagnosis. In populations where geophagia is traditional, it is not diagnosed as pica.