Dementia And Sleep

Dementia and sleep

Dementia and sleep are closely related. Many people with dementia complain of sleep problems. They may find it difficult to fall asleep. If they sleep, it might be short and fragmented. Poor sleep worsens dementia as sleep affects mental abilities. This article explores how dementia causes sleep problems and how lack of sleep affects dementia. 

What is dementia?

Dementia is a syndrome—it has symptoms that usually appear together. It impairs mental functions like thinking, reasoning, and remembering. Dementia is common in older people. But the symptoms of dementia differ from just getting older.

Dementia is not a disease. It results from gradual brain damage caused by certain diseases. This damage comes from the death of neurons or loss of connections between neurons.1,2 

There are different types of dementia

Dementia from Alzheimer’s disease.

Alzheimer's disease is the most common cause of dementia. It’s responsible for about 60–70% of dementia cases. Alzheimer’s disease is caused by the buildup of amyloid plaques and tau tangles and subsequent damage to the brain. Problems with thinking, memory, language, and perception are early signs of Alzheimer's disease.

Vascular dementia

This represents the second most common cause of dementia. Vascular dementia results from damage to the brain’s blood vessels caused by blockage of blood and oxygen flow to the brain. Vascular dementia usually occurs after a stroke. The early signs of this condition include problems with planning and decision-making.

Frontotemporal dementia

This is a rare type of dementia that usually affects people younger than 60. Pick’s disease or frontal lobe dementia are other names for it. Frontotemporal dementia is caused by the buildup of proteins, tau, and TDP-43. Its symptoms include difficulty with language and personality changes.

Lewy body disease

This consists of 2 closely related diseases—dementia with Lewy bodies and Parkinson's disease with dementia. It is caused by the deposition of Lewy bodies also known as alpha-synuclein. The early signs of Lewy body disease include short attention, movement problems, sleep disorders, hallucinations, and delusions.

Mixed dementia

This is dementia is caused by 2 or more conditions.1.2   

How dementia develops is not yet clear. But there are certain factors that increase the risk of dementia. Although factors like age and sex cannot be influenced, adopting a healthier lifestyle reduces the risk of dementia.

Symptoms of dementia

The symptoms of dementia are unique to each individual. The different types of dementia also have specific symptoms because each disease damages different parts of the brain. Dementia symptoms often start as mild and become severe at later stages.1,2,3

Some common early symptoms of dementia are:

  • Memory loss—difficulty remembering previous events
  • Confusion—not knowing what time it is or getting lost in a familiar place. 
  • Mood/behavior changes—acting impulsively, disregarding other people’s feelings
  • Problems having conversations—repeating questions, difficulty conveying thoughts, speaking, reading, or writing
  • Difficulty staying focused
  • Difficulty performing daily tasks.

In the early stages of dementia, mild dementia symptoms may go unnoticed by patients, family members, or doctors. If you feel like you or someone else might have early symptoms of dementia, you should contact a doctor to confirm. 

As dementia progresses, memory loss, communication, and behavioral problems usually get worse. Patients may also have other issues like movement problems, loss of appetite and weight, and behavioral changes. At late stages, patients may be unable to function on their own and may require constant assistance from a caregiver.3

There is currently no cure for dementia. But its symptoms can be alleviated using drugs and non-drug therapies.

Sleep problems are a common side effect of dementia

About 70% of people with early-stage dementia have sleep problems. While it’s normal for sleep quality to decline as people get older, sleep problems caused by dementia are usually more severe. Sleep problems also worsen dementia, reduce the quality of life of dementia patients, and pose problems for their caregivers.4,5,6 

Drugs can be used to treat sleep problems from dementia. Any sleep disorder or coexisting condition that worsens sleep also needs to be treated. Non-drug therapies are also effective. They include sleep hygiene education, physical and social activity, bright light therapy, and complementary alternative therapies such as massages, acupuncture, and acupressure.4 

Dementia causes sleep problems for different reasons:

  • Behavioral problems and the inability to make good decisions can affect sleep hygiene. For example, forgetting to turn off the light and eliminate noise, taking caffeine or excess fluids before bed.6
  • Dementia patients may misinterpret nighttime experiences. For example, they may perceive dreams as reality, they may have visual hallucinations in darkness, and they may also not recognize a sleeping partner. These could result in tormenting night experiences and poor sleep.6
  • Dementia interferes with circadian rhythm. This commonly affects Alzheimer's patients. The circadian rhythm controls the sleep-wake cycle. So, patients may confuse night and day, and sleep earlier or later than usual. They may wake up early and feel the need to prepare for the day while others are still asleep. Patients may also experience sundowning and become more agitated and confused in the late afternoon and early evening.4,6,7
  • People with Lewy body disease often experience insomnia. They may find it hard to fall asleep, have fragmented sleep, have nightmares, or wake up too early.4
  • The medications for dementia can disrupt sleep. For example, cholinesterase inhibitors like donepezil, galantamine, or rivastigmine can cause vivid dreams. Some patients avoid this effect by taking cholinesterase inhibitors during the day but this fix doesn’t work for all patients.6 Drugs used to treat comorbid conditions (inhalers for asthma, antihypertensives) also affect sleep.4 Doctors usually weigh the side effects of any drug with its benefits before prescribing them. So, ask your doctor to review drugs for possible negative effects on sleep.  
  • Other problems dementia patients usually experience such as pain, discomfort or depression contribute to nighttime sleep problems.4

Lack of sleep worsens symptoms 

The effect of sleep on dementia is bidirectional. Dementia causes problems with sleep and lack of sleep worsens dementia symptoms.5 

  • Lack of sleep in dementia patients means they won’t get the benefits of quality sleep. This may affect the clearance of toxic substances (such as amyloid in Alzheimer's disease) memory formation and mental capabilities the next day.6 
  • Lack of sleep causes fatigue. And fatigue makes it hard to perform mental tasks which are already difficult for dementia patients.6
  • Lack of sleep also causes daytime sleepiness. Dementia patients may even experience sleep attacks where they suddenly need to sleep at odd times. Daytime sleepiness reduces the zeal to engage in social activities and therapies. It might be risky for patients to perform activities like driving. These worsen dementia and quality of life.4 

Sleep may also play a role in the onset of dementia. Sleeping too short (less than 5 hours) or too long (more than 9 hours) is associated with dementia risk, especially from Alzheimer's disease. Poor sleep quality in midlife is also associated with dementia risk. As such, better sleep helps reduce the risk of dementia.5 

Sleep disorders also contribute to dementia risk. For example, 50–80% of people with rapid eye movement sleep behavior disorder develop Lewy body disease.5 Also, obstructive sleep apnea increases the risk of vascular dementia. Oversleeping is common in late-stage dementia as a side effect of mental and physical exhaustion.

It is common for people with late-stage dementia to spend a lot of time sleeping both during the day and at night.7 It's possible that they won’t remain fully awake for one hour a day.5

As dementia progresses, patients may become frailer and weaker due to brain damage. Sleeping pills and drugs used to treat dementia or other illnesses may also contribute to sleepiness. Patients may find it difficult to communicate, eat or understand their environment. So, they might not want to stay awake.7

Oversleeping in late-stage dementia is no cause for alarm. But patients might need assistance from professionals to prevent physical health problems.7  

If you are caring for a person with dementia, you can ask to review their drugs with a doctor or pharmacist. While patients are sleeping, you should make sure their environment is safe and conducive and that they can easily find you when they wake up. But if you notice an unusual increase in sleep you should talk to your doctor.


Dementia is often associated with sleep problems. Because of the symptoms of dementia, brain damage, drugs used to treat dementia, and other coexisting conditions, sleep is usually poor in dementia. This is a problem because sleep problems worsen dementia and overall quality of life. Healthcare professionals, patients, and their caregivers should not overlook sleep when managing dementia. It’s important that dementia patients and people with high dementia risk try to get good quality sleep.


  1. What Is Dementia? Symptoms, Types, and Diagnosis [Internet]. National Institute on Aging. [cited 2022 Sep 28]. Available from:
  2. What is dementia? | Alzheimer’s Society [Internet]. [cited 2022 Sep 28]. Available from:  
  3. Symptoms of dementia [Internet]. NHS.UK. 2017 [cited 2022 Sep 28]. Available from: 
  4. Ooms S, Ju YE. Treatment of sleep disorders in dementia. Curr Treat Options Neurol [Internet]. 2016 Sep [cited 2022 Sep 28];18(9):40. Available from: 
  5. Wennberg A, Wu M, Rosenberg P, Spira A. Sleep disturbance, cognitive decline, and dementia: a review. Semin Neurol [Internet]. 2017 Aug [cited 2022 Sep 28];37(04):395–406. Available from: 
  6. Shenker JI, Singh G. Sleep and dementia. Mo Med. 2017 Aug;114(4):311–5.
  7. Is it typical for people with dementia to sleep a lot during the day? | Alzheimer’s Society [Internet]. [cited 2022 Sep 28]. Available from: 

Roseline Akpa

Bachelor of Science degree in Human Physiology, Ahmadu Bello University, Nigeria

She is a freelance health writer interested in mental health, holistic health, and health tech. presents all health information in line with our terms and conditions. It is essential to understand that the medical information available on our platform is not intended to substitute the relationship between a patient and their physician or doctor, as well as any medical guidance they offer. Always consult with a healthcare professional before making any decisions based on the information found on our website.
Klarity is a citizen-centric health data management platform that enables citizens to securely access, control and share their own health data. Klarity Health Library aims to provide clear and evidence-based health and wellness related informative articles. 
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