Pica is a medical disorder characterized by an appetite for substances largely non-nutritive (e.g., metal, clay, coal, sand, dirt, soil, feces, chalk, pens and pencils, paper, batteries, spoons, toothbrushes, soap, mucus, latex gloves, ash, gum, lip balm, tacks and other office supplies, etc.) For these actions to be considered pica, they must persist for more than one month at an age where eating such objects is considered developmentally inappropriate. The name of the condition originates from the Latin word for magpie, a bird that is reputed to eat almost anything. Pica is seen in all ages, particularly in pregnant women, small children, and those with developmental disabilities.
Pica is more common in women and children. Pica in children (usually only in young children or children with autism or another mental or developmental disorder) may be dangerous. Children eating painted plaster containing lead may suffer brain damage from lead poisoning. There is a similar risk from eating dirt near roads that existed prior to the phaseout of tetra-ethyl lead in petrol(in some countries) or prior to the cessation of the use of contaminated oil (either used or containing toxic PCBs or dioxin) to settle dust. In addition to poisoning, there is also a much greater risk of gastro-intestinal obstruction or tearing in the stomach. This is also true in animals. Another risk of dirt-eating is the possible ingestion of animal faeces and accompanying parasites. Pica can also be found in animals and is most commonly found in dogs.
The scant research that has been done on the causes of pica suggests that the disorder is a specific appetite caused by mineral deficiency in many cases, such as iron deficiency, which sometimes is a result of celiac disease or hookworm infection. Often the substance eaten by someone with pica contains the mineral in which that individual is deficient.More recently, cases of pica have been tied to the obsessive–compulsive spectrum, and there is a move to consider OCD in the etiology of pica; however, pica is currently recognized as a mental disorder by the widely used Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). Sensory, physiological, cultural and psychosocial perspectives have also been used by some to explain the causation of pica.
It has been proposed that mental-health conditions, such as obsessive-compulsive disorder (OCD) and schizophrenia, can sometimes cause pica. It has been suggested that stress associated with traumatic events is linked to pica disorder. Some of the traumatic events common in individuals with pica include maternal deprivation, parental separation or neglect, child abuse, disorganized family structure and poor parent-child interaction.
However pica can also be a cultural practice not associated with a deficiency or disorder. Ingestion of kaolin (white dirt) among African-American women in the US state of Georgia shows the practice there to be a DSM-IV “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 health benefits such as the ability of clay to absorb plant toxins and protect against toxic alkaloids and tannic acids.
Unlike in humans, pica in dogs or cats may be a sign of immune-mediated hemolytic anemia, especially when it involves eating substances such as tile grout, concrete dust and sand. Dogs exhibiting this form of pica should be tested for anemia with a CBC or at least hematocrit levels. However since it may be an evolved natural mechanism to increase micronutrient levels this type of geophagia may not be accurately described as pica since it is not actually a diseased behaviour.
Treatment for pica is based on the category of patient (e.g. child, developmentally disabled, pregnant or psychotic) and may emphasize psychosocial, environmental and family-guidance approaches. An initial approach often involves screening for and, if necessary, treating any mineral deficiencies or other comorbid conditions. For pica that appears to be of psychotic etiology, therapy and medication such as SSRIs have been used successfully. However previous reports have cautioned against the use of medication until all non-psychotic etiologies have been ruled out.
Some medications may be helpful in reducing the abnormal eating behaviour if pica occurs in the course of a developmental disorder such as mental retardation or pervasive developmental disorder. These medications enhance dopaminergic functioning, which is believed to be associated with the occurrence of pica.Usually after pregnant women give birth pica subsides.
Zinc was successful at treating pica in a study of 703 Chinese preschool children.
Behaviour-based treatment options can be useful for developmentally disabled and mentally retarded individuals with pica. These may involve associating negative consequences with eating non-food items or good consequences with normal behaviour and may be contingent on pica being attempted or initiated regardless of a pica attempt. A recent study classified nine such classes of behavioural intervention:
- Presentation of attention, food or toys, not contingent on pica being attempted
- Differential reinforcement, with positive reinforcement if pica is not attempted and consequences if pica is attempted
- Discrimination training between edible and inedible items, with negative consequences if pica is attempted
- Visual screening, with eyes covered for a short time after pica is attempted
- Aversive presentation, contingent on pica being attempted:
- oral taste (e.g. lemon)
- smell sensation (e.g. ammonia)
- physical sensation (e.g. water mist in face)
- Physical restraint:
- self-protection devices that prohibit placement of objects in the mouth
- brief restraint contingent on pica being attempted
- Time-out contingent on pica being attempted
- Overcorrection, with attempted pica resulting in required washing of self, disposal of nonedible objects and chore-based punishment
- Negative practice (non-edible object held against patient’s mouth without allowing ingestion)
Few studies have been conducted to measure the prevalence of pica in various populations. A study published in 1994 found that 8.1% of pregnant African-American women in the U.S. self-reported pagophagia, the ingestion of large quantities of ice and freezer frost. A study conducted in 1991 found a prevalence of pica in 8.8% of pregnant women in Saudi Arabia. Rates of pica among pregnant women in developing countries, however, can be much higher, with estimates of 63.7% and 74.0%reported for two different African populations. This is due to different cultural norms as well as greater levels of malnutrition. Two studies of mentally retarded adults living in institutions found that 21.8% and 25.8% of these groups suffered from pica. Prevalence rates for children with and without developmental disabilities are unknown.
- Amylophagia (consumption of starch)
- Coprophagy (consumption of feces)
- Geophagy (consumption of soil, clay, or chalk)
- Hyalophagia (consumption of glass)
- Consumption of dust or sand has been reported among iron-deficient patients.
- Mucophagia (consumption of mucus)
- Odowa (soft stones eaten by pregnant women in Kenya)
- Pagophagia (pathological consumption of ice)
- Self-cannibalism (rare condition where body parts may be consumed;)
- Trichophagia (consumption of hair or wool)
- Urophagia (consumption of urine)
- Xylophagia (consumption of wood or paper)