| domain | best-supported finding | key statistic/evidence | suggested ontology terms | evidence caveat |
|---|---|---|---|---|
| Definition / diagnosis | Pica is persistent ingestion of non-nutritive, non-food substances for at least 1 month, inappropriate to developmental stage and not culturally normative | DSM-style criteria summarized in review literature; ALSPAC authors note available cohort items did **not** capture full DSM criteria such as 1-month duration or cultural/developmental exclusion (pqac-00000005, pqac-00000007) | Candidate terms: pica; abnormal eating behavior; ingestion of nonfood substance; HPO candidate: pica | Much epidemiology measures **pica behavior** rather than confirmed DSM/ICD diagnosis |
| Autism / developmental disability epidemiology | Pica is substantially more common in children with ASD and in DD subgroups with ASD traits and/or ID | SEED study: ASD 23.2%, DD 8.4%, population controls 3.5%; ASD+ID 28.1%, ASD without ID 14.0%, DD with both ID and ASD characteristics 26.3%; adjusted prevalence ratios 4.4-8.0 (pqac-00000011, pqac-00000013) | Candidate terms: autism spectrum disorder; intellectual disability; developmental delay; feeding and eating disorder | Cross-sectional ascertainment via questionnaire item, not formal pica diagnosis; preschool-enriched sample limits generalization |
| General-childhood epidemiology | In general-population childhood cohorts, pica appears uncommon and tends to decline with age | ALSPAC: 312/10,109 children (3.08%) had reported pica behavior; highest at 36 months 2.29% (226 cases); recurrence at 2+ waves in 19.55%; prevalence declined to 0.33% by 115 months (pqac-00000000, pqac-00000014) | Candidate terms: childhood onset; recurrent behavior; pediatric feeding disorder phenotype | ALSPAC measured caregiver-reported behavior, not fully adjudicated diagnosis |
| Iron / anemia association | Iron deficiency and anemia are among the most consistently reported biological associations with pica | Review summarizes strong association with iron deficiency anemia; meta-analysis cited therein found pica cases had 2.35-fold greater odds of anemia; geophagia may reduce iron absorption and pagophagia is commonly linked with iron deficiency (pqac-00000001, pqac-00000005) | Candidate terms: iron deficiency anemia; geophagia; pagophagia; laboratory abnormality: low hemoglobin / iron deficiency | Evidence is largely associative and directionality remains unresolved; primary meta-analysis not directly extracted here |
| Complications | Major harms are gastrointestinal, toxicologic, infectious, dental, and nutritional | Reported complications include dental enamel erosion, infection/parasites, lead intoxication, anemia, choking, poisoning, intestinal obstruction/perforation, and other GI complications (pqac-00000009, pqac-00000013, pqac-00000005) | Candidate terms: intestinal obstruction; gastrointestinal perforation; lead poisoning; parasitic infection; dental enamel erosion; anemia | Complication frequency is poorly quantified; many reports derive from case series/reviews and severe presentations |
| Behavioral treatment | Best-supported management is behavioral assessment plus function-based intervention and environmental restriction of unsafe items | Fields et al. note empirical support for applied behavior analysis and functional analysis to identify sensory-seeking, automatic reinforcement, or social functions; prevention strategies include close monitoring, restricting access, childproof locks, and attention-occupying activities (pqac-00000010) | Candidate MAXO terms: behavioral therapy; applied behavior analysis; functional behavioral assessment; environmental modification; caregiver education | Evidence base is mainly specialized behavioral literature and case series; high-quality disorder-specific RCT evidence is limited in retrieved context |
| Genetics / omics gap | No established monogenic cause, susceptibility gene set, or validated omics signature is currently supported for pica as a primary psychiatric diagnosis | Retrieved disease-focused evidence emphasizes psychosocial, developmental, and micronutrient associations; no causal genes, pathogenic variants, transcriptomic, proteomic, metabolomic, or epigenomic biomarkers were identified in retrieved pica-specific sources (pqac-00000003, pqac-00000010) | Candidate terms: multifactorial disorder; gene-environment interaction; evidence gap | Absence here reflects current retrieved evidence, not proof of impossibility; comorbid neurodevelopmental disorders may have independent genetic etiologies |
| Animal-model gap | No standard experimental animal model for human psychiatric pica was identified in retrieved disease-focused literature | Veterinary literature notes pica-like behavior in animals, but retrieved search did not yield a validated translational model reproducing the human DSM/ICD syndrome (pqac-00000010) | Candidate terms: animal behavior abnormality; comparative phenotype; model-organism evidence gap | Important distinction between veterinary pica-like behaviors and a human psychiatric feeding/eating disorder construct |


*Table: This table condenses the most useful ontology-ready evidence for pica across diagnosis, epidemiology, complications, treatment, and evidence gaps. It is designed to support knowledge-base curation while clearly separating strong findings from limitations in the available literature.*