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Delirium

Delirium and dementia

Delirium happens suddenly over a few hours or days. It can quickly cause a person to feel more confused, upset, anxious, or sleepier than usual. 

Delirium can last a few days to many weeks, and it can take weeks or months to recover.

Dementia is a slow, steady decline in mental skills like memory and thinking. It happens over several months or years. Alzheimer’s disease is 1 type of dementia.

It can be hard to know when someone with dementia has delirium. You may notice a sudden change in how they act. You may notice they can’t do things as well as usual or have trouble paying attention. 

An important first step is to tell a doctor, nurse, or other healthcare provider about the changes you see in a family member, friend, or yourself. Checking on these small changes early can make a difference.

If you have questions about delirium or dementia, call Health Link at 811. You can talk to a registered nurse​ and ask about the Dementia Advice Line.




Current as of: February 10, 2026

Author: Seniors Health and Continuing Care, Assisted Living Alberta