About this symptom
Memory loss is forgetting more than is usual for you. Confusion is trouble thinking as clearly or quickly as usual: not knowing where you are or what day it is, or finding it hard to pay attention, remember or decide.
Mild forgetfulness is common, especially when you are tired, stressed or not sleeping well, and many causes are treatable. Sudden confusion is different. It can be life-threatening and needs medical help at once. Memory trouble that is slowly getting worse and starting to affect daily life needs a doctor's assessment, because dementia is one possible cause.
Possible causes
This is not a diagnosis. These are the causes doctors think about, with the ones that are most urgent to rule out first.
- StrokeSudden confusion or trouble speaking or understanding, often with numbness or weakness on one side, trouble seeing or a severe headache. A mini-stroke can cause the same signs briefly.Read about it
- Head injury and concussionConfusion or memory trouble after a blow to the head needs checking at once.Read about it
- Urinary tract infectionInfections, including urine infections, can cause sudden confusion, especially in older people and people with dementia.Read about it
- Low blood sugarIn someone with diabetes, sudden confusion can be a sign of low blood sugar and needs urgent medical help.
- Medicines, alcohol or drugsConfusion or poor memory that began after a new medicine, heavy drinking or drug use, or when alcohol is stopped suddenly.
- DementiaMemory and thinking slowly get worse and start to get in the way of daily life. A doctor needs to assess it, and dementia is not the only possible cause.Read about it
- DepressionLow mood can make it hard to concentrate and remember. Stress, anxiety and poor sleep do the same, and all of these are treatable.Read about it
- Low vitamin B12 or thyroid problemsA lack of vitamin B12 or a thyroid problem can affect memory and thinking. Both can be checked with a blood test.
When to get help
Also get emergency care for:
- Confusion in someone with diabetes, who may have low blood sugar
- A confused person who may harm themselves or others
See a doctor soon if you have:
- Forgetfulness that is becoming more noticeable over weeks or months
- Trouble with everyday tasks, following a conversation or finding words
- Memory problems that affect your day-to-day life
- Low mood, mood changes or constant worry along with forgetfulness
- Forgetfulness that began after a new medicine, or with heavy alcohol use
- A relative or friend who has noticed changes in your memory, or you are worried about an older relative
Occasional slips, such as forgetting a name, with no change in daily life, can wait for a routine visit.
What you can do at home
Home care never replaces a doctor's check. With any emergency sign, call for an ambulance first.
Do
- Stay with a confused person, tell them who you are and where they are, and keep the surroundings calm and quiet
- Use a calendar and a clock, and write down medicine times and important tasks
- Note when the problems began, with examples, and bring all the medicines taken
- Take a relative or friend to the appointment who can describe the changes
- Look after sleep, low mood and worry, which can make memory worse
Do not
- Do not leave a confused person alone
- Do not ask a confused person many questions
- Do not stop a medicine, or start a new one or a supplement, without asking the doctor
What the doctor will do
The doctor will ask how the problem began and changed over time, how it affects everyday tasks, and about your medicines, alcohol, mood, sleep and other illnesses. They will examine you and usually talk to a relative or friend too. They may ask simple questions about the date, the time and where you are, or give a short memory and thinking test.
Tests depend on the likely cause. They may include:
- Blood and urine tests, for example for infection, blood sugar, vitamin B12 and thyroid disease
- A CT or of the head
- An EEG, a recording of the brain's electrical activity, if seizures are possible
- A referral to a memory specialist for more detailed assessment
Treatment depends on the cause. For example, treating an infection often clears the confusion.
Myths and facts
Things people often say about this. Open each one to see what is true.
Myth“Forgetting things is a normal part of getting old, so there is no need to see a doctor.”What is true?
Fact
Mild forgetfulness can come with age, but memory loss that affects daily life is not something to put up with. Many causes can be treated, and treatment may work better when it starts early.
Myth“Sudden confusion in an older person is just old age or tiredness, and will settle by itself.”What is true?
Fact
Sudden confusion is never just old age. It can be caused by an infection, a stroke, low blood sugar or a medicine, and it needs medical help immediately.
Myth“Any memory loss means dementia.”What is true?
Fact
Dementia is one cause. Stress, anxiety, low mood, poor sleep, some medicines, alcohol, thyroid problems and low vitamin B12 can all affect memory, and several of these can be treated. A doctor has to find out which.
Questions to ask your doctor
Tick the ones you want answered and take them with you.
Common questions
What should I do if my parent suddenly becomes confused?
Treat it as an emergency. Go to the emergency department or call for an ambulance, and do not drive yourself. Stay with them, tell them who you are and where they are, speak in short, simple sentences, and take their medicines along.
How do I know when forgetfulness needs a doctor?
See a doctor if memory problems are affecting daily life, are getting worse, or worry you or your family. Only a doctor can tell the cause, so avoid guessing. Bring someone who can describe the changes they have noticed.
Can stress, anxiety or poor sleep affect memory?
Yes. Stress, anxiety, low mood and poor sleep are common and treatable causes of memory trouble. A doctor will still check for other causes, so do not assume that is all it is if the problem is growing.
Can a urine infection make an older person confused?
Yes. Infections, including urine infections, can cause sudden confusion, especially in older people and people with dementia. Sudden confusion needs urgent medical care so the cause can be treated.