Delirium

Last reviewed Saturday, October 24, 2026

Delirium is a sudden change in how the brain is working that causes confusion and poor attention. It comes on over hours or days, often gets better and worse through the day, and is caused by a physical problem such as an infection, a medicine or alcohol. It’s a medical emergency, most common in older or seriously ill people.

Also called: acute confusional state; sudden confusion. Delirium in severe alcohol withdrawal is called delirium tremens, or “the DTs”.

Signs and symptoms

A person with delirium may:

not think or speak clearly, and lose the thread of a conversation
not know where they are, or what day it is
struggle to pay attention or remember things
see or hear things that aren’t there
sleep in the day and be awake and restless at night

It takes three forms:

Hyperactive: restless, agitated or aggressive.
Hypoactive: withdrawn, quiet and sleepy. This form is often missed, because the person just seems tired.
Mixed: moving between the two.

A quick check: ask the person their name, their age and today’s date. If they’re unsure or can’t answer, they probably need medical help.

Causes

Delirium comes from a physical problem in the body or brain, and often more than one. Common causes include:

infections, such as a urine infection in an older person, severe malaria or Lassa fever
a stroke, a head injury or some kinds of seizure
low blood sugar in someone with diabetes
some prescription medicines
alcohol poisoning or withdrawal, and drugs
carbon monoxide poisoning, especially if others in the house feel unwell too
serious lung or heart problems

The risk is highest in people aged 65 or over, people with dementia, people who are seriously ill, and people recovering from surgery or a broken hip.

Treatment

Doctors look for the cause and treat it, for example an infection, dehydration, low blood sugar or a medicine that needs changing. Calm, familiar care helps the brain recover:

family or friends visiting, and telling the person where they are and what’s happening
their glasses and hearing aids, within reach and working
enough to drink, and help to get up and walk
quiet nights, with as little disturbance as possible

Doctors use medicine to calm someone only briefly, and only when other ways of settling them haven’t worked. Many people improve once the cause is treated. But delirium is serious: it raises the risk of dying and of developing dementia later, so older people should have their memory checked afterwards.

In Nigeria

Delirium is common in Nigerian hospitals, and often missed. At a teaching hospital in South-West Nigeria, about 1 in 5 people aged 60 or over on the medical wards had it. In Enugu, about 1 in 4 people aged 65 or over developed it after surgery, and the teams caring for them missed 9 in 10 of those cases.

At a Nigerian psychiatric clinic, nearly 1 in 5 new referrals turned out to have delirium, mostly from infections, and most of them had put their symptoms down to a spiritual cause. Whatever the family suspects, sudden confusion needs a hospital first.

Delirium vs dementia

Onset: delirium comes on suddenly, over hours or days. Dementia develops slowly, over months or years.
Attention: poor attention is a hallmark of delirium. In dementia, memory and thinking decline gradually.
Course: delirium changes through the day and often improves when the cause is treated. Dementia keeps getting worse.

The two often overlap. Dementia raises the risk of delirium, and a sudden change in someone with dementia may be delirium on top. When it’s unclear which it is, doctors treat the delirium first.

When to get help

If someone suddenly becomes confused, treat it as an emergency: call 112 (or 767 in Lagos) or take them to the nearest emergency unit. If you’re the one affected, don’t drive yourself. Take their medicines along, stay with them, and reassure them in short, simple sentences. Tell the staff what the person is usually like, so they can see how much has changed. A child who suddenly becomes confused, especially with a fever, needs emergency care too.

Someone who drinks heavily every day should get medical advice before stopping, because severe withdrawal can be dangerous.

Caring for someone through delirium is exhausting. Carers can book a licensed therapist on Mytherapist.ng for themselves, for example for stress and burnout.

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