Pica is the persistent ingestion of nonnutritive, nonfood substances for at least one month at a developmental stage where the behavior is inappropriate, and it sits in the DSM-5-TR Feeding and Eating Disorders chapter alongside avoidant/restrictive food intake disorder and rumination disorder. Although often dismissed as a childhood curiosity, pica is clinically consequential: lead toxicity, intestinal obstruction, parasitic infection, dental injury, and iron-deficiency anemia are well-described complications, and the behavior is overrepresented in pregnancy, intellectual disability, autism spectrum disorder, and iron- or zinc-deficient states. ICD-11 places pica under feeding or eating disorders (6B84) with broadly aligned criteria. The clinician's first job is to recognize it, ask about it directly, and rule out medical sequelae and treatable nutritional deficiencies before turning to behavioral management. Bottom line: pica is a behavior with a medical workup attached, and missing the workup is the most common mistake.

True population prevalence is hard to pin down because patients rarely volunteer the behavior and clinicians rarely ask. Estimates vary widely by population studied, definition used, and method of ascertainment.^1-2

General population

• Prevalence in community samples of children is reported in the range of 4 to 26 percent depending on age and definition, with most behavior remitting by mid-childhood.^1-2
• Adult community prevalence is poorly characterized but considered low outside of risk groups.¹

High-risk populations

• Pregnancy is the single most common adult context, with international prevalence estimates ranging widely (commonly cited near 28 to 30 percent in pooled analyses, with marked geographic variation).³
  • Geophagia (earth, clay) and pagophagia (ice) predominate in pregnant patients.³
• Intellectual disability is a major risk context; reported prevalence rises with severity of disability and institutional settings.^1,4
• Autism spectrum disorder is associated with pica, particularly in children with co-occurring intellectual disability.⁴
• Iron-deficiency anemia, zinc deficiency, and sickle cell disease are repeatedly associated with pagophagia and geophagia.^5-6

Demographics and comorbidity

• No consistent sex difference in childhood pica; in adults, female predominance reflects the pregnancy and iron-deficiency populations.^1,3
• Pica clusters with other feeding and eating disorders, obsessive-compulsive spectrum behaviors, and trichotillomania-trichophagia in select patients.⁷
• Food insecurity, poverty, and cultural practice influence both prevalence and the substances ingested.³

Pica is best understood as a final common behavior with several distinct causal pathways, not a unitary disorder. The clinician's task is to identify which pathway dominates in the patient in front of them.^1,7

Nutritional hypothesis

• Iron deficiency is the most consistent nutritional association, particularly with pagophagia, and several studies report cessation of ice craving within days to weeks of iron repletion.^5-6
• Zinc and other micronutrient deficiencies have been implicated less consistently.⁶
• Whether deficiency causes the craving or the craving causes deficiency through displaced caloric intake is debated; both directions likely operate.^5-6

Neurobiological considerations

• Dopaminergic dysregulation has been hypothesized given the association with iron deficiency (iron is a cofactor for tyrosine hydroxylase) and the overlap with restless legs syndrome, also iron- and dopamine-linked.⁵
• Imaging and circuit-level data specific to pica are sparse; most neurobiological inference is borrowed from related compulsive and stereotyped behaviors.⁷

Developmental and behavioral factors

• In intellectual disability and autism spectrum disorder, pica often functions as Stereotypy or self-stimulation, maintained by sensory consequences or by attention contingencies.⁴
• Operant analysis frequently identifies automatic (sensory) reinforcement rather than social reinforcement, which shapes treatment.⁴

Cultural and environmental factors

• Geophagia is normative in some cultural and religious contexts and is not, in isolation, diagnostic of a disorder.³
• Toxin exposure, especially lead from paint chips and contaminated soil, is the dominant environmental hazard rather than an etiology of the behavior itself.⁸

DSM-5-TR places pica in the Feeding and Eating Disorders chapter, and the criteria are short but exacting. The diagnosis turns on duration, developmental appropriateness, and cultural context.⁹

DSM-5-TR criteria

• Persistent eating of nonnutritive, nonfood substances for at least one month.⁹
• The eating behavior is inappropriate to the developmental level, with a minimum age of approximately two years used in practice to exclude normal mouthing in infancy.⁹
• The behavior is not part of a culturally supported or socially normative practice.⁹
• If the behavior occurs in the context of another mental disorder (for example intellectual developmental disorder or autism spectrum disorder) or a medical condition (including pregnancy), it is severe enough to warrant additional clinical attention.⁹

Specifier

• In remission: full criteria were previously met but have not been met for a sustained period.⁹

ICD-11 alignment

• ICD-11 codes pica under feeding or eating disorders (6B84) with criteria that broadly mirror DSM-5-TR, including the developmental appropriateness and cultural-practice exclusions.¹⁰

Substances ingested are diverse and partly predict the medical complication profile. Eliciting the specific substance, frequency, and duration is more useful than asking whether the patient "eats nonfood items."^1,7

Commonly ingested substances and their named forms:

• Geophagia — earth, clay, soil; common in pregnancy and in some cultural contexts.³
• Pagophagia — ice; strongly associated with iron-deficiency anemia.^5-6
• Amylophagia — raw starch, including laundry starch and uncooked rice; reported in pregnancy.³
• Trichophagia — hair; can produce trichobezoars and is associated with trichotillomania.⁷
• Other: paint chips, plaster, paper, chalk, cigarette ashes, coffee grounds, metal objects, feces (coprophagia, which raises the differential of dementia, psychosis, or severe developmental disability).^1,7

Course

• In typically developing children, pica usually remits by adolescence.¹
• In intellectual disability, the behavior often persists into adulthood and may be lifelong without targeted intervention.⁴
• In pregnancy, the behavior typically resolves postpartum and with correction of iron deficiency.^3,5

Red flags requiring urgent evaluation

• Acute abdominal pain, vomiting, or obstipation (suggests bowel obstruction or perforation).⁷
• Lead exposure history or pagophagia with neurocognitive symptoms.⁸
• Ingestion of sharp or metallic objects.⁷
• Coprophagia in a previously continent adult (raises the differential of frontotemporal dementia or psychosis).⁷

Most diagnostic errors arise from missing pica entirely rather than misclassifying it. When the behavior is identified, the differential is narrower than it appears.^1,7

Other feeding and eating disorders

• Anorexia nervosa: ingestion of low-calorie items (ice, paper) may be driven by hunger suppression or caloric restriction rather than pica per se; consider when restrictive eating dominates the picture.⁹
• Avoidant/restrictive food intake disorder (ARFID): characterized by avoidance, not by ingestion of nonfood items.⁹
• Rumination disorder: repeated regurgitation, not nonfood ingestion.⁹

Neurodevelopmental and neurocognitive disorders

• Intellectual developmental disorder and autism spectrum disorder: pica may be diagnosed concurrently when severity warrants attention.⁹
• Major neurocognitive disorder, particularly frontotemporal: new-onset coprophagia or indiscriminate ingestion in an older adult should prompt cognitive evaluation.⁷

Psychotic disorders

• Ingestion of nonfood items in response to delusional beliefs (for example, command hallucinations or somatic delusions) is better classified as a symptom of the primary psychotic illness.⁷

Obsessive-compulsive spectrum

• Trichotillomania with trichophagia: hair pulling is the primary behavior; the ingestion is secondary.⁷
• Body-focused repetitive behaviors more broadly may overlap with pica in presentation.⁷

Medical mimics and contributors

• Iron-deficiency anemia and other micronutrient deficiencies: not exclusions but commonly causative or contributory.^5-6
• Pregnancy: a recognized context rather than an exclusion.³
• Lead toxicity: a complication of pica more often than a cause, but lead encephalopathy can produce its own behavioral disturbance.⁸

Assessment proceeds in two parallel tracks: characterize the behavior, and rule out medical sequelae and treatable deficiencies. The behavior is often elicited only by direct, specific questioning.^1,7

History

• Specific substances ingested, frequency, duration, amount, and circumstances (alone, in response to craving, in response to social cues).¹
• Onset relative to pregnancy, menarche, weight loss, or iron loss.^3,5
• Developmental history, including intellectual disability and autism spectrum diagnoses.⁴
• Cultural and family practices regarding geophagia or other ingestions.³
• Functional assessment in patients with intellectual disability: antecedents, consequences, and setting events maintaining the behavior.⁴
• Toxic exposure history, including age of housing, occupational lead exposure, and proximity to industrial sites.⁸

Physical examination

• General nutritional status, dentition, and oral mucosa.⁷
• Abdominal examination for distension, tenderness, or mass suggestive of bezoar or obstruction.⁷
• Neurological examination, including signs of lead toxicity (peripheral neuropathy, encephalopathy in severe cases).⁸

Laboratory and imaging workup

• Complete blood count with indices, ferritin, iron studies, and reticulocyte count to evaluate for iron-deficiency anemia.^5-6
• Zinc and other micronutrients when clinically indicated.⁶
• Blood lead level in any patient with geophagia, paint or plaster ingestion, or pediatric pica; venous sample preferred for confirmation.⁸
• Stool studies for ova and parasites in geophagia.³
• Abdominal imaging (radiograph, ultrasound, or CT) when bezoar, obstruction, or perforation is suspected.⁷
• Pregnancy testing in patients of reproductive capacity.³

Validated instruments

• No widely adopted, pica-specific validated rating scale is in routine clinical use; assessment relies on structured interview, functional analysis in developmental populations, and ad hoc behavior diaries.^1,4

Treatment follows the dominant pathway identified during assessment: correct nutritional deficiency, address medical complications, and apply behavioral intervention scaled to the developmental and clinical context. There is no FDA-approved pharmacotherapy specifically for pica.^1,4-5

Pharmacotherapy

• Iron repletion is commonly recommended in pagophagia and in other pica presentations with documented iron deficiency, and limited evidence suggests rapid reduction in ice craving following repletion.^5-6
• Treatment of an associated psychiatric disorder (for example, obsessive-compulsive disorder, psychotic disorder, or major depressive disorder) may secondarily reduce pica, but evidence for SSRIs or antipsychotics targeting pica itself is limited.⁷
• Some experts recommend cautious use of Atypical antipsychotics for severe, refractory pica in intellectual disability when behavioral intervention alone is insufficient, though high-quality evidence is lacking and the metabolic and movement-disorder risks are real.^4,7

Psychotherapy and behavioral intervention

• Applied behavior analysis is the most evidence-supported approach in intellectual disability and autism spectrum disorder, with strategies tailored to the function identified by functional analysis.⁴
  • Differential reinforcement of other or alternative behavior.⁴
  • Response interruption and redirection.⁴
  • Environmental enrichment to reduce automatic reinforcement.⁴
  • Discrimination training distinguishing edible from inedible items.⁴
• Cognitive behavioral therapy may be useful in cognitively intact adults, though the evidence base is small and largely descriptive.⁷
• Caregiver education and supervision are central in pediatric and developmental populations.⁴

Neuromodulation

• No established role.⁷

Adjunctive

• Environmental safety: removal of accessible nonfood items, lead-paint remediation, and supervised mealtimes in high-risk settings.⁸
• Nutritional counseling and structured meals to address food insecurity or restrictive eating patterns contributing to the behavior.³
• Treatment of parasitic infection when identified.³
• In pregnancy, prenatal counseling and iron supplementation are commonly recommended; reassurance about postpartum remission is appropriate when complications are absent.^3,5

Most pica-related morbidity is medical rather than psychiatric. The harms picture is dominated by toxicity, mechanical injury, and infection, and is concentrated in patients with prolonged or high-volume ingestion.^1,7-8

• Common adverse effects: dental erosion and dental fracture, particularly with pagophagia; constipation; abdominal discomfort.⁷
• Serious or rare adverse effects:
  • Lead toxicity with neurocognitive and developmental consequences, particularly in children.⁸
  • Intestinal obstruction, bezoar formation (including trichobezoar with Rapunzel syndrome in trichophagia), and bowel perforation.⁷
  • Parasitic infection from geophagia.³
  • Iron-deficiency anemia worsened by displacement of nutritive intake.^5-6
  • Electrolyte disturbances with specific substances, including hypokalemia from clay binding of dietary potassium in geophagia.⁷
• Monitoring burden: serial blood lead levels in exposed patients, hemoglobin and ferritin trajectories, growth monitoring in children, and behavioral data collection in applied behavior analysis programs.^4,8
• Limitations of the evidence base:
  • Most behavioral evidence is from single-case experimental designs in developmental populations, limiting generalizability.⁴
  • Pharmacotherapy evidence is dominated by case reports.⁷
  • Pregnancy data are largely cross-sectional and subject to underreporting.³
  • No widely validated, pica-specific outcome measure exists, complicating cross-study comparison.¹

Pica behaves differently across the lifespan and across comorbid contexts; treatment selection follows accordingly.^1,3-4

Pediatric

• Mouthing in children under two is developmentally normative and does not meet criteria.⁹
• In school-aged children, screen for lead exposure, iron deficiency, and food insecurity; pica is a marker for these as much as a behavior to extinguish.⁸
• Caregiver-mediated behavioral intervention is the mainstay.⁴

Intellectual disability and autism spectrum disorder

• Functional analysis should drive intervention selection; automatic reinforcement predominates.⁴
• Supervision and environmental modification are necessary adjuncts to skill-based intervention.⁴
• Antipsychotic use is common in practice but should be reserved and time-limited given metabolic and movement-disorder risks.^4,7

Perinatal

• Ask directly at every prenatal visit; prevalence is high and disclosure is low.³
• Check iron studies and lead level; supplement iron and counsel on substance-specific risks (lead in pottery, parasites in soil).^3,5,8
• Most cases remit postpartum without specific psychiatric treatment.³

Geriatric

• New-onset pica in an older adult, particularly coprophagia or indiscriminate ingestion, raises concern for major neurocognitive disorder of frontotemporal type and warrants cognitive evaluation.⁷

Comorbid substance use and psychiatric illness

• Pica in active psychosis may reflect command hallucinations or somatic delusions; treat the primary disorder.⁷
• Pica with restrictive eating patterns warrants evaluation for anorexia nervosa or ARFID.⁹

Cultural considerations

• Geophagia in some communities is normative and not, by itself, diagnostic; the cultural-practice exclusion in DSM-5-TR and ICD-11 is meaningful.^3,9-10
• Clinical judgment is required when culturally accepted practice produces medical harm; harm is not waived by cultural sanction.³

Outcome is favorable in most pediatric and pregnancy cases and more guarded in intellectual disability. Mortality is rare but real, driven by mechanical and toxic complications rather than the behavior itself.^1,4,7

• Pediatric pica typically remits by adolescence in the absence of intellectual disability.¹
• Pregnancy-related pica typically resolves postpartum, particularly with iron repletion.^3,5
• In intellectual disability, the behavior is often chronic and requires ongoing behavioral programming and supervision.⁴
• Mortality from intestinal perforation and acute lead toxicity is documented in case series, particularly in institutional settings with inadequate supervision.^4,8
• Functional impact is greatest in developmental disability populations, where pica can limit community placement and quality of life.⁴

Emergencies in pica are medical first and psychiatric second. The presenting complaint is rarely the pica itself.^7-8

• Acute abdomen in a patient with known pica: image early; bezoars and perforation are documented complications.⁷
• Suspected lead encephalopathy (irritability, ataxia, seizures, altered mental status in a child with exposure): emergent venous blood lead level and admission for chelation evaluation.⁸
• Ingestion of sharp or metallic objects: surgical or endoscopic evaluation per local protocol.⁷
• Severe self-injurious pica in intellectual disability may warrant hospitalization for behavioral stabilization, environmental control, and caregiver training.⁴
• Psychiatric admission is rarely indicated for pica alone; admit when comorbid psychiatric illness, severe self-injury, or imminent medical danger is present.⁷

Pica sits at the intersection of nutrition, behavior, and culture, and the resulting controversies are mostly about where to draw lines. The evidence base is too thin to settle most of them with confidence.^1,3,7

• Causation vs. correlation with iron deficiency: whether iron deficiency drives pica or pica drives iron deficiency through displacement remains debated, and the direction may differ by patient.^5-6
• Where to place culturally sanctioned geophagia: the DSM-5-TR exclusion is principled but operationally difficult when the same practice produces measurable medical harm.^3,9
• Role of antipsychotics in developmental disability: prescribing is common but evidence is weak, and the metabolic and movement-disorder risks may exceed the symptomatic benefit.^4,7
• Adult pica without intellectual disability or pregnancy is poorly characterized in the literature, and the boundary with obsessive-compulsive spectrum disorders is unsettled.⁷
• Lack of a validated, pica-specific outcome measure limits the ability to compare interventions across studies.¹

• Pica requires persistent ingestion of nonnutritive, nonfood substances for at least one month, with a developmental floor of approximately two years.⁹
• The behavior must not be a culturally supported or socially normative practice to qualify for the diagnosis.⁹
• Pica can be diagnosed concurrently with intellectual developmental disorder, autism spectrum disorder, or pregnancy when severity warrants clinical attention.⁹
• Pagophagia (ice eating) is strongly associated with iron-deficiency anemia and often remits with iron repletion.^5-6
• Geophagia (earth or clay) is the most common form in pregnancy and raises risk for lead exposure and parasitic infection.^3,8
• Trichophagia can produce trichobezoars, including Rapunzel syndrome in which a gastric trichobezoar extends through the pylorus into the small bowel.⁷
• Blood lead level is a required workup in any patient with geophagia, paint or plaster ingestion, or pediatric pica.⁸
• Applied behavior analysis with function-based intervention is the most evidence-supported treatment in intellectual disability and autism spectrum disorder.⁴
• No medication is FDA-approved specifically for pica; pharmacotherapy targets nutritional deficiency or comorbid psychiatric illness.^1,5,7
• Coprophagia or indiscriminate ingestion in a previously continent older adult should prompt evaluation for major neurocognitive disorder, particularly of frontotemporal type.⁷
• ICD-11 classifies pica under feeding or eating disorders (6B84) with criteria aligned to DSM-5-TR.¹⁰
• Pregnancy-related pica typically remits postpartum, particularly with correction of iron deficiency.^3,5

Funding: none. Conflicts of interest: none declared. Peer-review status: draft, not yet peer-reviewed.