Prader-Willi Syndrome, psychosis and sensory integration and processing may not seem, at first glance, to belong in the same conversation.

Yet a paper from the University of Cambridge invites us to think more carefully about Psychosis Sensory Integration and Processing. It suggests that Prader-Willi Syndrome, often known as PWS, may offer an important window into how genes, brain development, sensory processing, emotional regulation and psychosis vulnerability can interact. The authors from the Department of Psychiatry argue that genetically determined neurodevelopmental conditions associated with higher rates of psychotic illness can help us understand neural pathways that may also matter in wider mental health populations. For those of us working in services for people with psychosis, sensory integration and processing matters deeply and has real clinical value for practice.

Because the paper does not place distress, altered perception or emotional dysregulation only in the language of “behaviour”. It places them in the body, the brain, the nervous system, the environment and the person’s lived experience of safety.

That is an important shift.

Prader-Willi Syndrome and psychosis risk

Prader-Willi Syndrome is a complex genetic neurodevelopmental condition linked with early hypotonia, feeding differences, later hyperphagia, growth and hormonal differences, cognitive differences and varied emotional and mental health needs. It is associated with different genetic subtypes, including paternal deletion and maternal uniparental disomy, often shortened to mUPD.

The Cambridge paper highlights that people with PWS may share some common patterns of non-psychotic psychopathology, including mood lability, repetitive and ritualistic actions, temper outbursts and skin picking. However, rates of psychotic illness appear to be markedly higher in people with the mUPD subtype than in those with the deletion subtype.

This distinction matters because it suggests that psychosis risk is not simply about external presentation. It may relate to specific genetic and neural pathways. The authors propose that altered expression of genes on chromosome 15 may affect GABA and glutamate systems, which are central to the brain’s excitatory and inhibitory balance. They link this to mood regulation, sensory processing and psychotic illness.

In simpler terms, the paper asks us to consider what happens when the brain’s systems for filtering, organising, inhibiting, and responding to information are working differently. We know clinically that foundational sensory inputs from inside and outside interact and underpin executive function, cognition, and emotional and social actions. In reality, this interplay is typically interrelated – it is likely happening across all of these areas at once, with sensory registration being foundational .

Why sensory integration and processing belong in the formulation

One of the most important practice implications is this: sensory processing should not be treated as an optional add-on.

The Cambridge paper specifically links psychosis vulnerability with sensory processing, GABA and glutamate balance, auditory processing, processing speed and sensory gating. It describes findings in PWS where some people have difficulty separating human voices from background noise and may begin a response before sensory information has been fully processed. That sentence alone should make us pause in our clinical practice.

How often do we describe a person as not listening, refusing, overreacting, attention seeking, rigid or controlling, when the nervous system may be struggling to filter what is important from what is overwhelming In a busy classroom, hospital ward, clinic, supported living home or family kitchen, this could be the difference between participation and distress.

A person may be trying to process speech, background noise, visual movement, hunger, fatigue, body discomfort, social expectation, uncertainty and emotional tone at the same time. If the brain is slower to organise sensory information or less able to inhibit irrelevant input, the world may feel unpredictable and unsafe.

That does not excuse every action. But it does change the question. Instead of asking, “How do we stop this behaviour?” we might instead need to ask, “What is the person’s nervous system trying to manage?”

That is a much more human and clinically useful starting point.

Sensory gating, threat and overwhelm

The paper also discusses sensory gating, including P50 sensory gating, which has been studied in schizophrenia. Sensory gating is part of how the brain filters repeated or less relevant sensory input. When this filtering is compromised, the person may experience the world as too intense, too crowded or too hard to organise. As we teach and lecture on our workshops and modules, this has direct relevance for sensory integration and processing.

Poor sensory gating may mean that the person cannot easily ignore the hum of lights, the scrape of chairs, the tone of a voice, the movement of people nearby, the texture of clothing, internal body sensations or the emotional charge in a room.

For some people, the difficulty may not be that they are “too sensitive” in a simple sense. It may be that their brain and body are working very hard to decide what matters now. When too much arrives together, distress may rise quickly. The person may seek control, withdraw, repeat actions, become angry, freeze, refuse, leave, shout, shut down or become more confused. Seen through a sensory lens, these responses are not random. They may be embodied attempts to create predictability, reduce uncertainty or regain safety.

Vestibular, postural and body-based processing

Rose et al. (2024) found that children with Prader-Willi Syndrome showed differences in sensory reception and integration for postural control, particularly in conditions requiring greater reliance on vestibular input.

Their study adds an important body-based layer. Rose and colleagues examined sensory reception and integration abilities in children with and without PWS. They found that children with PWS showed lower overall postural control and increased sway compared with children with obesity. The findings suggested particular difficulty adapting when vestibular input needed to be prioritised for balance.

This matters because posture is not just about standing still. Postural control supports looking, listening, reaching, sitting, moving, playing, eating, learning and joining in. If balance, vestibular processing, proprioception and postural control are less secure, the person may have to work much harder simply to stay organised in everyday activity. The study authors recommend postural control activities that help people weigh sensory information in changing sensory environments, with particular attention to the vestibular system.

This fits closely with Ayres Sensory Integration thinking.

The vestibular system, triggered by head movement and contributing to balance, works closely with proprioception from stretch receptors in muscles, ligaments and tendons. Together, these systems support body awareness, postural security, movement planning and confidence in action. When these systems are not well integrated, participation can become effortful. The person may look anxious, avoidant, controlling or oppositional.

But underneath, their body may not feel safe enough, steady enough or organised enough to do what is being asked. Irritability as a sensory question It is also interesting that a newly indexed 2026 study is examining associations between sensory processing and irritability in people with PWS. The study included 101 individuals and investigated whether sensory processing contributes independently to irritability.

That direction of research feels important.

Irritability is often described as a behavioural or psychiatric concern. It may be. But it may also be shaped by sensory load, interoceptive confusion, pain, sleep, hunger, fatigue, auditory overwhelm, postural insecurity, social demand and difficulty predicting what will happen next.

For practice, this means sensory integration and processing assessment should be part of the wider formulation, not separated into a neat “sensory box”.

The person’s sensory world may be one route through which emotional distress becomes visible.

What this means for practice

For therapists, educators, families and support teams, the message is not that sensory processing causes psychosis. That would be too simple and too risky.

A more careful message is this:

Sensory integration and processing differences may be one important part of a wider neurodevelopmental pattern involving genetic vulnerability, sensory gating, processing speed, emotional regulation, sleep, interoception, postural control, relational stress and environmental demand.

That gives us a better formulation. It also gives us more compassionate and practical questions.

• What sensory information is the person receiving?
• What is being missed, amplified, confused or poorly filtered?
• What happens when speech, sound, movement, hunger, fatigue, touch, uncertainty and emotional demand arrive together?
• How does the person’s body show us early signs of overload?
• What helps the person feel safer before distress escalates?
• What do adults need to change in their relational response?

This is where tools like Sensory Ladders® can be so valuable.

Sensory Ladders® can help the person, family and team notice body cues, sensory triggers, early warning signs and supportive responses across different states. For some people, this will be verbal and reflective. For others, it may need to be built through observation, family knowledge, staff reflection, photos, objects, movement cues, visual supports and repeated shared noticing.

The aim is not to make the person label emotions neatly. The aim is to understand embodied states and support participation.

A PEAR TREE Lens

Through a PEAR TREE Lens, the implications become even clearer.

Person

The person is not a problem to be managed. They are a sensory being with a unique nervous system, history, health context, communication style, strengths, fears, motivations and ways of seeking safety.

Environment

Noisy, cluttered, unpredictable or socially demanding environments may increase sensory load. A busy dining room, classroom, clinic waiting area or ward may place very high demands on auditory figure-ground processing, postural control, interoception and emotional regulation.

Activity

Activities involving food, waiting, transition, uncertainty, movement, social interpretation or change may be especially demanding. The question is not only whether the person can do the task, but what sensory and emotional demands the task carries.

Relational response

The adult response can either reduce or increase sensory threat. A calm voice, fewer words, a predictable rhythm, time to process, attuned support, and respectful adaptation may help the person organise. Fast instructions, correction, raised voices, or too many demands may increase overload.

TREE

Triage asks: What matters most right now?
Relationships – Intentional use of self and relational infrastructure. How do we create safety through our responses, as individuals and teams?
Embodied Evaluation asks: what is the body showing us?
Ethical Choice asks: how do we adapt with dignity, justice and clinical honesty, creating pragmatic solutions for practice?

This is sensory-informed practice at its best; not a list of strategies. Not a behaviour plan with sensory words added. Not a generic recommendation for “sensory breaks”. This is careful, co-produced, person-led reasoning about how the body, brain, environment, activity and relationships come together.

A final thought

The Cambridge paper gives us a powerful reminder that sensory processing belongs in serious clinical conversations. It belongs in mental health. It belongs in a neurodevelopmental formulation. It belongs in discussions about psychosis vulnerability, emotional safety, participation and care.

For people with Prader-Willi Syndrome, and for many others with complex neurodevelopmental and mental health needs, sensory integration and processing may shape how the world is received, filtered, understood and responded to.

When we recognise this, we stop asking the person to carry all the responsibility for distress.

We start asking better questions of the environment, the activity, the relational response and the systems around them.

And that is where more human, more effective support can begin.

Read more about this study by a group of researchers in the Department of Psychiatry, University of Cambridge: https://api.repository.cam.ac.uk/server/api/core/bitstreams/6e0eb466-ee94-4fa6-8ed1-0a9ca976e12f/content