Pica and Polydipsia: Diagnosis Is Insufficient, Needs-Led Support Matters

Cite this article as: Batalla-Duran, L. (2026). Pica and polydipsia: Diagnosis is insufficient, needs-led support matters. Ability Bridge SEND. https://www.abilitybridgesend.co.uk

A diagnosis is not a safeguarding strategy

Prioritising diagnosis appears to be the standard response to pica, while polydipsia can similarly become treated as though the label itself explains the behaviour.

An inconvenient truth is that a diagnosis will not safeguard a child or young person from choking or poisoning simply because a clinician has named the behaviour.

It is not unusual to hear, “It’s OK, they don’t have a diagnosis of pica,” when a child or young person puts something inedible in their mouth. Conversely, “Yes, it’s OK, that’s normal, they have pica.”

Neither response safeguards the child or young person. Having a diagnosis, or not having one, does not make putting an unsafe item into the mouth or ingesting bleach safe.

The immediate question should not simply be, “Do they have a diagnosis?” It should be: “What does this child or young person need to be safe right now?”

When a baby begins to crawl and explore the world by putting things in their mouth, parents and carers do not wait for a diagnosis before responding to the risk. Nor do they dismiss the risk simply because mouthing is a normal stage of human development.

They respond to the need. They make the environment safer, remove potential hazards and meet need by providing larger, safer items that allow the baby to mouth, explore and discover the world.

That same principle applies to pica and polydipsia: we must not wait for a label before safeguarding a child or young person by meeting need.

When the risk is already visible

Pica and polydipsia behaviour is directly observable to teaching staff, parents and carers without specialist equipment. The DSM-5-TR describes pica as the persistent eating of non-nutritive, non-food substances where this is developmentally inappropriate (American Psychiatric Association [APA], 2022). Pica can also occur alongside autism and intellectual disability (Attia & Walsh, 2025). The ICD-11 similarly recognises pica as the regular consumption of non-nutritive substances requiring clinical attention (World Health Organization [WHO], 2024).

Polydipsia is excessive thirst and an overwhelming urge to drink fluids (Cleveland Clinic, 2022). We can see someone repeatedly seeking and consuming unusually large amounts of fluid or attempting to drink dirty washing-up water. Unlike pica, polydipsia is not used as a diagnosis, but as a symptom or clinical presentation that requires investigation into its possible underlying cause. We do not need a label to describe the behaviour to recognise a safeguarding risk or the need for medical investigation. Seeing the behaviour does not tell us why it is happening, which is why understanding the underlying need matters.

Polydipsia is particularly useful in illustrating this distinction: excessive thirst and drinking may be treated as a symptom prompting investigation into its underlying cause. This raises an important question for pica too: rather than allowing the diagnostic label to become the explanation, should we be asking what is driving the behaviour and what need sits beneath it?

This does not make professional assessment unimportant. Diagnosis has an essential role, particularly where clinical assessment may identify medical consequences or underlying medical issues requiring attention. However, we do not need to wait for diagnostic confirmation of pica, or identification of the underlying cause of polydipsia, before acting on an observable medical risk. This is where diagnosis alone can be insufficient and, paradoxically, waiting for it can delay the support a child or young person needs. Diagnosis should not become the gateway through which safeguarding has to pass.

Where the risk is already observable, diagnosis or identification of an underlying cause should not be treated as a prerequisite for action. Where a safety concern is visible, waiting for diagnostic confirmation or investigation before taking action can itself create a safeguarding risk.

This is particularly important with polydipsia. If a child or young person is repeatedly drinking unusually large amounts, the behaviour itself should prompt medical assessment to investigate what may be causing it. Excessive thirst and drinking can be symptoms of conditions including diabetes mellitus and diabetes insipidus, which require different investigations and timely treatment. We see the behaviour, recognise the potential risk, and investigate the cause (NHS, 2022a, NHS, 2022b).

Diagnosis and safeguarding are not the same thing

A parent, carer or teacher can observe and document a child or young person repeatedly ingesting stones, paper, soil or other inedible items, or consuming unusually large amounts or harmful fluid, including how long it has been happening and, where relevant, whether it forms part of the family’s cultural practices.

If everyone is focused on establishing a diagnostic threshold or finding a label for the behaviour, we risk overlooking the far more immediate question: What does this child or young person need today to reduce the risk of harm??

Support should not wait for diagnosis

Although you do not need a formal diagnosis to put support in place, a parent, carer or education professional can document the observed behaviours and record ‘pica as a working consideration’ and/or describe observed polydipsia. This records what is being seen and considered; it is not a formal clinical diagnosis.

GPs can sometimes be reluctant to diagnose pica without what they consider sufficient evidence. This can be frustrating, particularly when the behaviours themselves are clearly observable. With polydipsia, however, the important clinical question is not simply whether the behaviour can be given that label, but what is causing the excessive thirst and drinking.

Recording ‘pica as a working consideration’ where appropriate, alongside a clear description of observed pica and/or polydipsia behaviours, ensures that what is happening is documented without presenting observation as a formal clinical diagnosis.

For school leaders, therefore, the question is not whether support should wait for diagnostic confirmation or identification of an underlying cause, but whether systems are embedded to recognise pica and polydipsia behaviours, mitigate risk, identify and understand need, and respond consistently by meeting that need.

What does the behaviour tell us about need?

The question is not when will they get a diagnosis but what need is the behaviour meeting, and how can we meet that need more safely?

This requires more than an individual member of staff responding to incidents as they arise. School leaders need to build a culture in which staff are encouraged, and feel safe, to notice, describe, document and explore behaviour through the lens of need. What is the child or young person seeking, avoiding, communicating or regulating? What can we learn from when, where and how the behaviour occurs?

This also means joined-up working. Families, education staff and relevant health and social care professionals may each hold different pieces of information. Collaboration allows us to understand the need, identify possible underlying causes and find safer, more appropriate ways of meeting it.

For example, where professional curiosity about pica behaviour indicates a sensory function, simply removing access to an unsafe item may reduce an immediate hazard but will leave the underlying sensory need unmet. In my experience, this can lead to dysregulation, potential self-harm, harm to those around the child or young person, and a more serious safeguarding issue as they become increasingly distressed in trying to meet that sensory need. Therefore, the key question becomes: can that sensory need be understood and met through safer alternatives, ideally advocated for by the child or young person themselves, their family and relevant professionals.

Why this matters for school leaders

This is where school leaders have an important role. A needs-led culture does not ask, “Do they have a diagnosis?” or “How do we stop this behaviour?” It asks, “What does this child or young person need to be safe right now, what is this behaviour telling us about need, and how can we work together to meet that need safely?”

Diagnosis may help us formally identify pica or establish an underlying cause for polydipsia, but it is not the starting point. Safeguarding and mitigating risk depends on how well we identify, understand and meet the needs that sit behind that confirmation.

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For schools wanting to explore needs-led approaches to supporting children and young people with pica and/or polydipsia behaviours, more information about Ability Bridge SEND's Understanding and Supporting Pica and Polydipsia in School Online Training is available here.

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References

American Psychiatric Association. (2022). Diagnostic and statistical manual of mental disorders (5th ed., text rev.; DSM-5-TR). American Psychiatric Association Publishing.

Attia, E., & Walsh, B. T. (2025). Pica. Merck Manual Professional Edition.

Cleveland Clinic. (2022, August 24). Polydipsia: Causes & treatment.

NHS. (2022a). Diabetes insipidus: Diagnosis. NHS.

NHS. (2022b). Excessive thirst. NHS

World Health Organization. (2024). Clinical descriptions and diagnostic requirements for ICD-11 mental, behavioural and neurodevelopmental disorders. World Health Organization.