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Pica (disorder)

Pica (disorder) is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Pica (disorder) rather than just read about it. In short: Pica ( PY-kə) is the psychologically compulsive craving or consumption of objects that are not normally intended to be consumed. It is classified as an eating disorder but can also be the result of an existing mental disorder.

Pica (disorder) — main illustration
Pica (disorder) — illustration

Key takeaways

  • Pica (disorder) belongs to biology; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Pica (disorder) to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Pica (disorder) from memory before moving on to harder problems.

Reference excerpt

Pica ( PY-kə) is the psychologically compulsive craving or consumption of objects that are not normally intended to be consumed. It is classified as an eating disorder but can also be the result of an existing mental disorder. The ingested or craved substance may be biological, natural, or manmade. The term was drawn directly from the Latin word for the Eurasian magpie, a bird subject to much folklore regarding its opportunistic feeding behaviors. According to the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5), pica as a standalone eating disorder must persist for more than one month at an age when eating such objects is considered developmentally inappropriate, not part of culturally sanctioned practice, and sufficiently severe to warrant clinical attention. Pica may lead to intoxication in children, which can result in an impairment of both physical and mental development. In addition, it can cause surgical emergencies to address intestinal obstructions, as well as more subtle symptoms such as nutritional deficiencies, particularly iron deficiency, as well as parasitosis. Pica has been linked to other mental disorders. Stressors such as psychological trauma, maternal deprivation, family issues, parental neglect, pregnancy, and a disorganized family structure are risk factors for pica. Pica is most commonly seen in pregnant women, small children, and people who may have developmental disorders such as autism. Children eating painted plaster containing lead may develop brain damage from lead poisoning. A similar risk exists from eating soil near roads that existed before the phase-out of tetraethyllead or that were sprayed with oil (to settle dust) contaminated by toxic PCBs or dioxin. In addition to poisoning, a much greater risk exists of gastrointestinal obstruction or tearing in the stomach. Another risk of eating soil is the ingestion of animal feces and accompanying parasites. Cases of severe bacterial infections occurrence (leptospirosis) in patients diagnosed with pica have also been reported. Pica can also be found in animals such as dogs and cats.

Signs and symptoms

Pica is the consumption of substances with no significant nutritional value such as soap, plaster, plastic or paint. Subtypes are characterized by the substance eaten:

This eating pattern should last at least one month to meet the time diagnostic criteria of pica.

Complications Complications may occur due to the substance consumed. For example, lead poisoning may result from the ingestion of paint or paint-soaked plaster, hairballs may cause intestinal obstruction, and Toxoplasma or Toxocara infections may follow ingestion of feces or soil.

Causes Pica is currently recognized as a mental disorder by the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). According to the DSM-5, mineral deficiencies are occasionally associated with pica, but biological abnormalities are rarely found. People practicing forms of pica, such as geophagy, pagophagy, and amylophagy, are more likely to be anemic or to have low hemoglobin concentration in their blood, lower levels of red blood cells (hematocrit), or lower plasma zinc levels. Specifically, practicing geophagy is more likely to be associated with anemia or low hemoglobin. Practicing pagophagy and amylophagy is more highly associated with anemia. Mental health conditions such as obsessive–compulsive disorder (OCD) and schizophrenia have been proposed as causes of pica. More recently, cases of pica have been tied to the obsessive–compulsive spectrum, and a move has arisen to consider OCD in the cause of pica. Sensory, physiological, cultural, and psychosocial perspectives have also been used to explain the causation of pica. Pica may be a cultural practice not associated with a deficiency or disorder. Ingestion of kaolin (white clay) among African American women in the US state of Georgia shows the practice to be a DSM-4 "culture-bound syndrome" and "not selectively associated with other psychopathology". Similar kaolin ingestion is also widespread in parts of Africa. Such practices may stem from purported health benefits, such as the ability of clay to absorb plant toxins and protect against toxic alkaloids and tannic acids.

Diagnosis No single test confirms pica, but because pica can occur in people who have lower than normal nutrient levels and poor nutrition (malnutrition), the health care provider should test blood levels of iron and zinc. Hemoglobin can also be checked to test for anemia. Lead levels should always be checked in children who may have eaten paint or objects covered in lead-paint dust. The healthcare provider should test and monitor for infection if the person has been eating contaminated soil or animal waste.

DSM-5 The DSM-5 posits four criteria that must be met for a person to be diagnosed with pica:

Person must have been eating non-nutritive nonfoods for at least one month. This eating must be considered abnormal for the person's stage of development. Eating these substances cannot be associated with a cultural practice that is considered normal in the social context of the individual. For people who currently have a medical condition (e.g.: pregnancy) or a mental disorder (e.g.: autism spectrum), the action of eating non-nutritive nonfoods should only be considered pica if it is dangerous and requires extra medical investigation or treatment on top of what they are already receiving for their pre-existing condition.

Differential diagnosis In individuals with autism, schizophrenia, and certain physical disorders (such as Kleine–Levin syndrome), non-nutritive substances may be eaten. In such instances, pica should only be noted as an additional diagnosis if the eating behaviour is sufficiently persistent and severe to warrant additional clinical attention.

… excerpt ends here. Continue reading the full article.

Illustrations

Pica (disorder) illustration
Pica (disorder): Chalky stone composed of kaolinite with traces of quartz, small pieces of which were sucked on by a person with pica
Chalky stone composed of kaolinite with traces of quartz, small pieces of which were sucked on by a person with pica

Worked examples

Example 1 — a first encounter with Pica (disorder)

Start with the simplest possible case. Write down what Pica (disorder) claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Pica (disorder) before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Pica (disorder) ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Pica (disorder)

In research
Pica (disorder) appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Pica (disorder) in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Pica (disorder) is common in secondary-school and first-year university syllabi. It links to neighbouring topics Animals by eating behaviors, Dog diseases, Eating behaviors of humans, so understanding it makes those chapters shorter.
In everyday life
Look for Pica (disorder) outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study Pica (disorder) in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Pica (disorder) means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Pica (disorder) out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Pica (disorder) in simple terms?

Pica ( PY-kə) is the psychologically compulsive craving or consumption of objects that are not normally intended to be consumed. It is classified as an eating disorder but can also be the result of an existing mental disorder.

Why does Pica (disorder) matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Pica (disorder)?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Pica (disorder).

Tags

  • Animals by eating behaviors
  • Dog diseases
  • Eating behaviors of humans
  • Eating disorders
  • Mental disorders diagnosed in childhood
  • Pica (disorder)

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