INFORMATION SHEET

Pica (Eating Inedible Objects)

What is pica?

Pica refers to eating objects which are inedible such as stones, faeces, clothing and
cigarette butts. Pica may be specific to just one inedible object or an individual may ingest a
variety of different inedible objects.

Research into causes, assessment and interventions for pica are extremely limited. This
information sheet is based on the research that is available and current clinical practice.

What are the risks?

Whilst some objects may pass harmlessly through the body, pica can be potentially life
threatening. Risks range from vomiting, constipation and infections to blockages in the gut
and intestines, choking and poisoning. In some cases, surgery may be needed to remove
objects from an individual’s gut or to repair tissue injuries.

 If you are worried about an individual who has eaten an inedible object it is very
important to contact their GP or your nearest accident and emergency department for
medical advice.

What causes pica?

The specific causes of pica are unknown, but certain conditions and situations can increase
an individual’s risk of developing pica, these are:
learning disabilities
autism
nutritional deficiencies
pregnancy.

It is estimated that between 4% and 26% of individuals with a learning disability display pica
behaviour1, 2, 3. It is thought that the more severe the individual’s learning disability the
greater the chance that they will display pica4.

Health checks

Pica can be associated with mineral deficiencies including iron and zinc5.

 A general health check should be conducted by the individual’s GP. Tests to rule out iron
and zinc deficiencies as the cause of pica should be considered.

There is also limited evidence which associates pica with mental health problems4.

 A psychiatric assessment to rule out mental health problems should be considered.

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Assessing pica

Functional Assessment

Functional assessment is the most commonly used way in which professionals such as
clinical psychologists and behavioural nurse specialists try to find out what the causes of
pica are. Functional assessment aims to look at why the individual is eating inedible
objects. Ways of reducing or eliminating the pica based on the causes identified during the
assessment are then used to form a behaviour support/intervention plan. Please see the
Challenging Behaviour Foundation Information sheet “Functional Assessment” for detailed
information on functional assessment.

A functional assessment usually involves a clinician interviewing the individual’s main carer
and the use of recording charts. However in some circumstances an analogue assessment
may be used. An analogue assessment is when artificial “test” situations are used to try to
establish what is causing the pica behaviour.

The reasons why individuals with learning disbailities engage in challenging behaviour are
usually explained in the following four ways:

1. Social attention

Does the individual receive a lot of attention as a result of ingesting inedible objects? If so
the individual may have learned that eating inedible objects means that they are rewarded
with lots of adult attention. Even if the attention is negative e.g. “no”, or shouting, this can
prove rewarding and may lead to the behaviour being repeated in the future. Additionally
the natural reaction when an individual eats an inedible object is concern and care, for
example, a hospital visit may be essential to ensure the individual’s wellbeing. However the
concern and care may also prove rewarding for the individual and increase the likelihood
that the behaviour will be repeated again in the future.

2. To obtain a favourite activity, object, food or drink (tangibles)

Does the individual receive a favourite object, activity or food or drink after ingesting
inedible items? If so the individual may have learned to associate eating inedible objects
with obtaining a favoured item and this may lead to the behaviour being repeated again in
order to obtain the favoured item. Additionally the activities of going to a hospital or doctor’s
surgery e.g. ride in an ambulance/car, waiting room, consultation etc. may prove rewarding
for the individual.

3. To escape from an activity or situation

Does the individual escape from tasks they don’t want to do or situations that they don’t
want to be in as a result of ingesting inedible items? If so then the individual may have
learned that eating inedible objects is associated with escape from disliked situations or
tasks. They are then more likely to repeat the pica behaviour in the future to avoid the
task/situation again.

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 -3-
4. Sensory feedback

Is the texture, taste, smell or visual information similar between objects? If so the individual
may have learned to associate eating particular inedible objects with experiencing an
enjoyable or unusual texture/taste/smell or visual information. Cigarettes are commonly
eaten by individuals with a severe learning disability. Research has shown that the nicotine
in cigarette butts reinforces the behaviour 6, 7. Additionally it is important that people
generally have things and activities in their life that they enjoy. If the individual lacks these
then boredom may result in pica.

Note that the individual who engages in pica to obtain attention or one of the other
consequences described above will not usually be deliberately or consciously seeking the
consequence. Rather, in situations of need, they behave automatically in ways which have
been successful in the past.

Interventions for pica

The following examples of interventions are not intended to be exhaustive but to provide
some examples of how clinicians and parents working in partnership can seek to eliminate
or reduce pica behaviour.

Interventions based on the cause(s) of pica

1.) Social attention

If pica is motivated by gaining social attention, an intervention strategy may include ignoring
the pica behaviour (only if it is safe to do so) or preventing the individual from eating the
object with the minimum possible attention. This may include not giving any eye contact,
maintaining a ‘neutral’ facial expression and using speech to issue instructions only (no
social chat) in a neutral tone of voice. Providing the individual with lots of positive social
attention when the individual is not engaging in pica is essential. Additionally trying to
increase the individual’s communication skills so that they have a less dangerous way of
requesting attention would be an important long term goal.

Case Study 1

After moving to a residential service, Samantha started to search out and swallow small
objects around the house. The behaviour developed over the course of a year, from her
picking up small items of fluff or paper from the floor and eating them, to swallowing coins,
pen tops, and other larger items, and this resulted in several trips to Accident and
Emergency. Staffing had been increased to monitor her continually and prevent the
behaviour, and although this reduced the frequency considerably, she still managed to find
small objects and swallow them, and continually looked for opportunities to do this. She was
observed for a period of several weeks, and the recordings showed that she was more
likely to engage in the behaviour when there were fewer staff present, and because of the
risk, staff reacted to the behaviour with a great deal of attention. It was felt that the
behaviour attracted and maintained staff attention, and had developed because she had
moved from a home environment where she had continual attention to one where she had
to share the attention of staff with other residents of the house, and she had learned that
putting things in her mouth resulted in a great deal of attention. An intervention was
developed where staff responded as little as possible when she ate something
inappropriate, but gave her large amounts of attention when she was engaging in other
© The Challenging Behaviour Foundation. Registered charity no. 1060714 (England and Wales). Registered office: The Old
Courthouse, New Road Avenue, Chatham, ME4 6BE. www.challengingbehaviour.org.uk.Tel. 01634 838739
 -4-
behaviours. The behaviour reduced significantly, but still re-emerges occasionally when
staffing levels are low.

2.) To obtain a favourite activity, object, food or drink (tangibles)

If pica is motivated by obtaining a favourite activity, object, food or drink an intervention

strategy may include making sure the individual is able to access their favourite
activity/object/food/drink without needing to eat an inedible item. Additionally working
towards increasing the individual’s communication skills so they have another way to
request their favourite activity/object/food/drink e.g. with a symbol or sign would be an
important long term goal.

3.) To escape from an activity or situation

If pica is motivated by escaping from an activity or situation an intervention strategy may

include looking for early warning signs (i.e. any behaviours that tend to occur prior to the
pica) that alert you to the possibility that the individual wants to end an activity or escape
from a situation. If possible try to end the task/move to a new situation before the individual
engages in pica. It is also important to look at why the individual wants to finish the activity.
Is it something they don’t like? Have they been doing it for too long? Is it too difficult?
An important long term goal would be working towards increasing the individual’s
communication skills so that they have a less dangerous way of saying “no” or “finished” or
“break”, e.g. signing “finished”.

Case Study 2

Susie shows a large number of repetitive behaviours that are associated with her autism.
She tries to spend a lot of time on her own and away from other people. She had developed
the behaviour of keeping small amounts of faecal material in her hand after visiting the
toilet, and putting this in her mouth. Clear records of the behaviour were kept, and it was
found that because of the behaviour, she was interacted with far less frequently than other
people she lived with, and carers openly said that they found it difficult to be with her
because of the behaviour. The observations suggested that she had developed the
behaviour because she was unable to communicate to carers when she needed to spend
time away from other people, but had learned that the behaviour allowed her to do this. A
communication system was developed where Susie could clearly indicate to others when
she wanted to be alone and staff would respect and facilitate this. Susie learned to use this
system very effectively and the eating of faecal material disappeared. Observations were
continued, and the amount of time she interacted with others actually increased. It was
thought that this was because once she had a reliable way of isolating herself, she felt more
in control of situations.

4.) Sensory feedback

If pica is motivated by sensory feedback e.g. the smell of the object, the colour of the object
or the texture of the object then an intervention plan may be based on providing the
individual with items which give the individual the same type of sensory feedback without
being harmful. Once an alternative has been identified this could be scheduled in as an
activity for certain times of the day to reduce the impact on the individual’s daily routine.

© The Challenging Behaviour Foundation. Registered charity no. 1060714 (England and Wales). Registered office: The Old
Courthouse, New Road Avenue, Chatham, ME4 6BE. www.challengingbehaviour.org.uk.Tel. 01634 838739
 -5-
Case Study 3

Ever since his family and carers could remember, Jimmy picked up cigarette butts in the
street and from ash trays and would chew them and keep a ball of chewed tobacco in his
hand. It had been thought that this was to get attention from others who spent a lot of time
trying to prevent the behaviour, and in getting him to give them the chewed tobacco. The
behaviour had significant health risks, and prevented Jimmy from participating in a number
of ordinary day to day activities. He was closely observed over a period of two weeks, and
one of the important observations was that the behaviour happened when he thought he
was on his own, and he would often put the tobacco that he had in his hand back into his
mouth. It was also noted that Jimmy had a lot of sensory behaviours, e.g. he liked playing
with water, running his hands over different textures etc. Following these observations, one
idea was that the behaviour was sensory (that he liked the very strong taste), another was
that he might be addicted to nicotine. Further observations suggested that even when he
was unable to engage in the behaviour that he did not show withdrawal symptoms. A
programme was devised to give him access to small amounts of very strong tasting foods
(anchovies, marmite), especially when he was more likely to eat tobacco. Over a short
period of time, Jimmy replaced the cigarette eating behaviour in favour of accessing the
strong tasting food.

Increasing the number of structured activities and levels of engagement with other people
has also been shown to reduce pica behaviour8. It is important to look at how many
structured daily activities the individual takes part in and consider whether this should be
increased to reduce boredom.

Other Interventions for Pica

Identifying incompatible/alternate behaviours (differential reinforcement)

Identifying behaviours which are incompatible with eating inedible objects and rewarding
the individual for using these alternate behaviours can reduce pica. For example if a student
eats inedible objects when he is moving from one classroom to another then instructing him
to keep his hands in his pockets when walking and rewarding him for doing so may be an
effective intervention as keeping hands in pockets is incompatible with picking up inedible
objects and putting them in the mouth.

Providing alternative forms of oral stimulation

Chewing gum, theratubing (cylindrical rubber tube which can be used to bite on) and
popcorn have been used to reduce pica. It is thought that they act as an alternative source
of oral stimulation. Different tastes and textures may need to be tried before a suitable
alternative is found.

Discrimination training

Does the individual think that everything is edible? Discrimination training involves explicitly
teaching an individual to discriminate between food and non-food items e.g. a sorting task
can be used and the individual asked to sort objects into edible and non-edible items. This
could then be turned into a visual chart displaying edible and non-edible items.

© The Challenging Behaviour Foundation. Registered charity no. 1060714 (England and Wales). Registered office: The Old
Courthouse, New Road Avenue, Chatham, ME4 6BE. www.challengingbehaviour.org.uk.Tel. 01634 838739
 -6-
Pica box

A pica box contains items which are safe for the individual to chew, mouth and/or ingest so
there is a supply of safe items on hand as an alternative to non-edible items. Items should
resemble the appearance or texture of the items the individual has shown a preference for
in the past. Initally the pica box should always be available to the individual. The amount of
time the pica box is available for can then be reduced over time.

Aversive techniques

Historically aversive techniques (unpleasant/punishing techniques) which inflict physical or

mental discomfort such as spraying water, ammonia, lemon and using devices such as a
helmet to place over the individuals head have all been used to treat pica. These
techniques are no longer recognised as acceptable practice and it would be expected that
every effort would be made to use non-aversive techniques.

What can you do?

Request a general health check from a GP to eliminate medical problems as the

cause of pica
Rule out iron and zinc deficiencies as the cause of pica by requesting a blood test
from a GP
Rule out mental health problems as the cause of pica by requesting a mental health
assessment
Ask your GP or social worker for a referral to a clinical psychologist or behavioural
specialist for an assessment of pica behaviour and an intervention plan to help
reduce or eliminate the pica behaviour
A functional assessment is the most common assessment used to identify the
causes of pica

Whilst you are waiting for an assessment and intervention/behaviour support plan to be put
in place the following may be considered:

As far as possible manage the individual’s environment so that ‘favoured’ non-edible

objects are out of reach/locked away. Specialist equipment may be necessary such
as virtually indestructible mattresses. Please see the Challenging Behaviour
Foundation information sheet “Specialist equipment and safety adaptations” for more
details.
Keep a careful record of the person’s attempts to eat inedible objects. What do they
try to eat? Under what circumstances? This kind of information will be very useful to
the assessment process
Close observation of the individual may limit the ingestion of non-edible items. If the
pica behaviour is severe and persistent you may wish to consider the following:

For a child: Make sure pica behaviour is included on the child’s statement of special
educational needs and insist that as pica can be life threatening the child is supervised
on a 1:1 ratio at all times. Details of hospital visits and medical appointments may be
helpful as local authority budgets are stretched and obtaining this level of support may
be very difficult. For more information see the Challenging Behaviour Foundation
information sheet “Getting a Statement” or contact your local Parent Partnership
Service.
© The Challenging Behaviour Foundation. Registered charity no. 1060714 (England and Wales). Registered office: The Old
Courthouse, New Road Avenue, Chatham, ME4 6BE. www.challengingbehaviour.org.uk.Tel. 01634 838739
 -7-

For an adult: Make sure that pica behaviour is detailed in the individual’s care plan and
person centred plan. If the individual requires 1:1 attention for the maintenance of their
safety insist that the individual receives this support. Details of hospital visits and
medical appointments may be helpful as local authority budgets are stretched and
obtaining this level of support may be very difficult. For more information on obtaining
support see “Fair Access to Care Services (FACS). Guidance on eligibility criteria for
adult social care”, Department of Health (2003).

References
1
Danford, D. E., and Huber, A. M. (1982). Pica among mentally retarded adults. American
Journal of Mental Deficiency, 87 (2), 141-146.
2
Dudley, J. R., Ahlgrim-Delzell, L., and Calhoun, M. L. (1999). Diverse diagnostic and
behavioural patterns amongst people with a dual diagnosis. Journal of Intellectual Disability
Research, 43, 70-79.
3
McAlpine, C., and Singh, N. (1986) Pica in Institutionalized Mentally Retarded Persons.
Journal of Mental Deficiency Research, 30 (2),171-8.
4
Dudley, R., Ahlgrim-Delzell., L and Calhoun, M. (1999) Diverse diagnostic and behavioural
patterns amougst people with a dual diagnosis. Journal of Intellectual Disability Research,
43, 70-79.
5
Pace, G. M., and Toyer, E. A (2000). The effects of a vitamin supplement on the pica of a
child with severe mental retardation. Journal of Applied Behavior Analysis, 33, 619-622.
6
Piazza, C. C., Hanley, G. P., & Fisher, W. W. (1996) Functional analysis and treatment of
cigarette pica. Journal of Applied Behavior Analysis, 29, 437-450.
7
Goh, H-L., Iwata, B. A., Kahng, S. W. (1999) Multicomponent assessment and treatment of
cigarette pica. Journal of Applied Behavior Analysis, 32, 297-316.
8
Mace, F. C., & Knight, D. (1986) Functional Analysis and Treatment of Severe Pica.
Journal of Applied Behavior Analysis. 19, 411-416.

Last updated July 2008

With thanks to:

Peter McGill, Tizard Centre, University of Kent at Canterbury for commenting on drafts of
this information sheet.

Allan Davis, Consultant Clinical Psychologist, Kent & Medway NHS and Social Care
Partnership Trust for providing the case studies.

© The Challenging Behaviour Foundation. Registered charity no. 1060714 (England and Wales). Registered office: The Old
Courthouse, New Road Avenue, Chatham, ME4 6BE. www.challengingbehaviour.org.uk.Tel. 01634 838739