Pica

Definition

DSM-5-TR Diagnostic Criteria

1. Persistent eating of non-nutritive, non-food substances for at least 1 month
2. The behavior is inappropriate to the developmental level of the individual (minimum age: 2 years)
3. Not part of a culturally supported or socially normative practice
4. If occurring in the context of another mental disorder (e.g., intellectual disability, ASD, schizophrenia), it is severe enough to warrant independent clinical attention

Common Substances Ingested (by Type)

Epidemiology

• True incidence is unknown; rare in healthy children >2 years in the US
• 75% of 12-month-old infants and 15% of 2-3-year-olds mouth non-nutritive objects (not diagnostic)
• 33.9% of children with sickle cell anemia in Detroit reported pica
• In sub-Saharan Africa, up to 77% of school-age children in some populations
• Prevalence in institutionalized individuals with intellectual disability: 10-33%
• Occurs in both males and females
• Associated with pregnancy (especially geophagia and amylophagia in pregnant women) - Kaplan & Sadock's Comprehensive Textbook of Psychiatry, p. 11419

Etiology

• Nutritional deficiency - Low plasma iron and zinc levels are associated with pica; iron and calcium deficiency in animal models induces pica-like behavior. Pagophagia (ice eating) is strongly linked to iron deficiency anemia.
• Psychosocial factors - Neglect, poor mother-child relationship, poverty, overcrowding
• Cultural factors - In some communities, geophagia is a culturally sanctioned practice (e.g., clay eating in parts of Africa and the American South)
• Neurodevelopmental - ASD and intellectual disability strongly predispose
• Organic - Hypozincemia and hypoferremia may drive craving behavior
• Psychiatric comorbidities - Schizophrenia, OCD, ARFID

Clinical Complications

• Kaplan and Sadock's Synopsis of Psychiatry, p. 530
• National Kidney Foundation Primer on Kidney Diseases notes baking soda pica in pregnancy as a cause of hypokalemic metabolic alkalosis and rhabdomyolysis.

Differential Diagnosis

• Normal developmental mouthing in infants (<2 years) - not pica
• Culturally sanctioned practices - not pica
• Anorexia nervosa with non-food ingestion to suppress appetite - not pica
• ARFID with sensory-driven restricted intake (may be comorbid)
• OCD, schizophrenia, ASD (pica can co-occur with all of these)
• Hair-pulling disorder (trichotillomania) when hair is swallowed

Course and Prognosis

• Most commonly begins in children aged 12-24 months
• Usually remits by adolescence in those without intellectual disability or ASD
• In pregnant women, typically limited to the duration of the pregnancy
• In children with severe neurodevelopmental disorders, it tends to persist
• Longitudinal data suggest associations with depression, personality disorders, and bulimia nervosa in adolescent years if untreated in early childhood - Kaplan & Sadock's Comprehensive Textbook of Psychiatry, p. 11420

Treatment

1. Identify and correct underlying deficiencies - Iron, zinc supplementation if deficient
2. Environmental modification - Remove access to ingested substances; lead-proof environment
3. Behavioral interventions - Aversive techniques, differential reinforcement of incompatible behaviors, exchanging inedible for edible items, environmental enrichment
4. Parent-child relationship therapy - Especially in young children; improving parental responsiveness reduces oral self-soothing
5. Social/protective services - Address poverty, neglect, overcrowding
6. Treat comorbid psychiatric conditions - ASD support programs, OCD management

• Kaplan & Sadock's Comprehensive Textbook of Psychiatry, p. 11420

Key Points to Remember

• Minimum age for diagnosis: 2 years
• Always check: iron, zinc, lead levels
• In pregnant women: geophagia and amylophagia are the most common forms; usually resolves after delivery
• Can be life-threatening (lead poisoning, intestinal obstruction, electrolyte disturbances)
• Most common comorbidities: intellectual disability, ASD, schizophrenia, OCD
• Pagophagia (compulsive ice eating) is a classic clinical clue for iron deficiency anemia