FamilyFX: The Family Reset System

Could pain or illness be changing my child’s behaviour?

How to notice when behaviour may reflect pain or illness, gather useful observations and get help without expecting a child to explain everything in words.

By FamilyFXWritten January 2026Published 6 August 2026Last reviewed 22 June 2026Next review due 22 June 20278 min readReviewed by FamilyFX
A woman and a child sit close on a sofa, her hand resting on the child's arm, both looking at each other in a softly lit living room.

The short answer

Consider health whenever behaviour is new, sharply worse or unlike the child's usual pattern. Pain may appear as withdrawal, agitation, disrupted sleep, refusal, self-injury, aggression or loss of skills, particularly when a child cannot locate or describe what hurts. Compare the change with their normal baseline, check eating, drinking, sleep, toileting, movement, skin, teeth, periods and recent medicines, and record what you observe without trying to diagnose the cause. Contact a GP or NHS 111 when you are concerned; use 999 for a life-threatening emergency. Continue to reduce distress and keep people safe while seeking help. A behavioural explanation should not be used to dismiss a physical-health change.

  • Treat a sudden or unexplained change from baseline as health information.
  • A child may show pain through movement, sleep, eating, toileting or behaviour rather than words.
  • Record concrete changes and timings instead of trying to name a diagnosis.
  • Seek medical advice when you are concerned and urgent help for an emergency.
  • Keep communication adjustments and familiar support available during assessment.

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