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Sudden confusion (delirium)

Sudden confusion (delirium) can have many different causes. Get medical help immediately if someone suddenly becomes confused (delirious).

If a person is confused, they may:

  • not be able to think or speak clearly or quickly
  • not know where they are (feel disorientated)
  • struggle to pay attention or remember things
  • see or hear things that are not there (hallucinations)

Try asking the person their name, their age and today's date. If they seem unsure or cannot answer you, they probably need medical help.


  • stay with the person – tell them who you are and where they are, and keep reassuring them

  • use simple words and short sentences

  • make a note of any medicines they're taking, if possible


  • do not ask lots of questions while they're feeling confused

  • do not stop the person moving around – unless they're in danger

Sudden confusion can be caused by many different things. Do not try to self-diagnose – get medical help if someone suddenly becomes confused or delirious.

Some of the most common causes of sudden confusion include: