Text size
Change contrast

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

How to tell if someone is confused

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 aren’t there (hallucinations)

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

See a GP if:

  • you’re worried that you or a relative are becoming increasingly forgetful or confused

It could be a sign of dementia. The symptoms of dementia often start gradually and get worse over time.

Go to A&E or call 999 for an ambulance if someone suddenly becomes confused

Many of the causes of sudden confusion need assessment and treatment as soon as possible. In some cases, it may be life threatening.

Things to do while you wait for an ambulance


  • 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

Causes of sudden confusion

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

Some of the most common causes of sudden confusion include:

Back to your health
The Royal Wolverhampton NHS Trust