Is Dementia a Mental Illness?

  • 1st Revision: Emma Soopramanien
  • 2nd Revision: Sophia Bradshaw
  • 3rd Revision: Keri Wilkie


A new case of dementia is diagnosed every 3 seconds in the world. Almost 75% of people globally with dementia have not been diagnosed, and 62% of healthcare practitioners incorrectly assume dementia is an inevitable consequence of ageing. With early diagnosis, accessing treatments options and breaking stigma against older people can significantly improve the quality of life for people living with dementia.


What is it?

Dementia is a decline in a person's ability to perform basic cognitive functions involved in thinking, remembering, reasoning, and social skills to a degree where it can impede a person's normal, daily life. Dementia itself is not a disease, but a term that describes a bundle of conditions and symptoms. Here are the most prominent diseases and disorders that are known to develop dementia symptoms:1

  1. Alzheimer’s Disease - Most common cause of dementia with trademark symptoms associated with memory and recall.2
  2.  Vascular Dementia - Second most common form of dementia resulting from restricted blood flow to the brain (i.e. stroke, diabetes, high cholesterol).3
  3. Lewy Body Dementia - Third most common form of dementia with a range of symptoms associated with balance, movement, alertness, and sleep.4
  4. Fronto-temporal Dementia - A type of dementia that impacts the front lobe of the brain that can severely impact a person’s personality, behaviour, and language.5
  5.  Mixed Dementia - A combination of two or more dementia types and/or diseases.6

A patient’s experience with dementia differs in severity and onset. While no treatment currently exists to cure dementia, available support and treatments can improve the lives of people living with dementia and their carers.


Dementia results from injuries and diseases that impact brain cells; therefore, interfering with normal brain functions involved in thinking, memory, movement, judgement, and communication. Each of these functions are controlled by different parts of the brain. 

Consequently, different types of dementia conditions are closely tied to where the damage is most prominent in the brain. Damage to the brain that results in dementia is, in most cases, permanent and progressively deteriorates over time. 


Because there are several symptoms, dementia can vary between people and patients. Symptoms and signs of dementia can be best understood in three stages:8

Early Onset Stage - It is difficult to diagnose dementia at this stage since the onset of dementia is gradual, and symptoms can be dismissed as normal parts of ageing:

  • Forgetfulness 
  • Losing track of time and thoughts
  • Getting lost in familiar places.
  • Confusion 

Middle Progressive Stage - Symptoms of dementia become clearer and patterns are notable:

  • Difficulty recalling the names of friends and family, recent events, and details from significant memories (e.g. weddings, loss of a family member, etc.).
  • Confusion at home - why they are in a certain room, etc.
  • Inability to finish a basic task independently.
  • Trouble communicating (e.g. incomplete thoughts, forgetting why they asked a question, inability to use appropriate vocabulary, etc.).
  • Behavioural changes (e.g. wandering, repeating thoughts and questions).

Late Debilitative Stage - Dementia symptoms progressively deteriorate to near-complete dependence to perform basic tasks: 

  • Struggle with or unable to recognize family and friends.
  • Significant behaviour changes include increased agitation, aggression, verbal abuse, and distress.
  • Trouble with basic movement such as walking, washing, using eating utensils, etc., thus requiring assistance.
  • Increasingly unaware of time and place.

Risk factors

There are preventable and unpreventable risk factors associated with the possibility of developing dementia. Early diagnosis is essential to take necessary steps to reduce preventable risk factors.

Preventable Risk Factors

Behaviours that Increase the Risk of Heart Disease

Medical conditions primarily associated with the heart, such as heart attack and stroke, impact oxygen supply to the brain, resulting in damage to the brain. The following are risk factors that increase the chance of heart disease:

  • Smoking
  • Harmful Consumption of Alcohol
  • Unhealthy Diet 
  • Physical Inactivity 

Depression, Social Isolation, and Cognitive Inactivity

These conditions are linked to changes in brain activity and chemistry that may contribute to developing dementia symptoms. 

Unpreventable Risk Factors


The risk of developing dementia significantly increases as individuals age. However, it is important to note that, despite the common misconception and stigma surrounding ageing and dementia, ageing does not inevitably lead to dementia - many people live without developing dementia.

Family History/Genetics

Most dementia is not passed down to children and grandchildren. While certain types of dementia may have a strong genetic link, they are rare. However, Huntington’s disease and familial prion disease have a chance of being inherited.9,10 

Traumatic Brain Injury

Trauma from physical accidents and diseases that affect the brain may increase the risk of developing dementia.

Is Dementia a Mental Illness?

Dementia is not a mental illness or mental disorder. To understand the distinctions between mental illness and dementia, it is first important to clearly define and distinguish the difference between mental health and mental illness.        

  • Mental health is overall wellbeing in areas of emotions, thinking, communication, learning, resilience, and self-esteem. It is an essential component of a person’s relational, personal, emotional, and social health.11 
  • Mental illnesses are diagnosed medical conditions involving significant changes in emotional, cognitive, and behavioural patterns and abilities.

Dementia is, first, about a person’s brain and its functions. Trauma and damage to the brain may increase the chance of developing dementia and dementia symptoms, such as cognitive impairment and memory loss. By extension, dementia can negatively impact a person’s mental health, and without prevention, may progress into mental illness.

The Relationship between Dementia and Mental Illness 

Dementia and Depression

At least 1 in 5 people will have experienced one depressive episode in their lifetime.12 According to the American Psychiatric Association, depression is a common, preventable, and successfully treatable mental illness that negatively affects your feelings, thoughts, and behaviour.13 There are many different types of depression, and they can all significantly affect your mental health and wellbeing.14

Depression and dementia overlap significantly in their symptoms and are known to be risk factors for each other. For example, major depressive disorder is common among up to 50% of patients with vascular dementia.15

Depression commonly occurs among patients with dementia, a reaction to the early cognitive deficit, and can become a risk factor for dementia. 

While dementia and depression share many symptoms, they have key differences that distinguish one from the other:16

Time to DevelopTakes a long to develop(months to years)Develops quicker than dementia (weeks to months)
SymptomsSpeech problems and loss of awareness is commonLoss of short and long-term memory is commonSpeech problems and loss of awareness is rareComplete loss of short and long-term memory is rare
Life courseDementia is progressive and irreversible. Can be periodic. Preventable and treatable

Dementia and Hallucinations

Mental illness and dementia can both lead to mild to severe hallucinations. Hallucinations come in many different forms, such as hearing, smelling, feeling, tasting, and seeing.17 While some might experience pleasant and comforting hallucinations, some struggle with highly distressing events, and with frequent episodes.

Accessing Support


You are not alone. There are currently 55 million people living with dementia, and 10 million cases are reported each year.8 Each year more and more people are finding the resources and support they need to prepare and live with dementia. Since there is no cure for dementia, it can be disheartening: Help is available. Furthermore, for carers, it is crucial to remember to take care of your own physical and mental health.

Useful Resources:

For Carers:

NHS Dementia Guide

For Information on Dementia

Alzheimer’s Association 

Alzheimer’s Society 

Alzheimer’s Organization 2021 Report

Mental Health

Mental health is equally as important as your physical health. Just as there are treatment options for the common cold and casts for broken bones, there are numerous options to ensure you maintain good mental health or live with a mental illness without affecting your quality of life. While the amount of available information on mental health is brilliant, it can feel overwhelming. Below are a few resources to get started and give you what you need.

Useful Resources:

Mental Health for Specific Category Groups

Digital Resources for Mental Health


Dementia can be difficult for a patient and their carers, but with early diagnosis and preparation, it is manageable. While there is no cure for dementia, a vast range of support is available. Increased dementia awareness and support are all leading towards a better environment of awareness, early action, and care.


  1. What Is Dementia? | CDC 2019. (accessed March 17, 2022).
  2. Alzheimer’s Disease Fact Sheet. National Institute on Aging n.d. (accessed March 17, 2022).
  3. Vascular Dementia Fact Sheet (MADRC). National Institute on Aging n.d.  (accessed March 17, 2022).
  4. Lewy Body Dementia Fact Sheet (MADRC). National Institute on Aging n.d.  (accessed March 17, 2022).
  5. Frontotemporal Dementia Fact Sheet (MADRC). National Institute on Aging n.d. (accessed March 17, 2022).
  6. Mixed Dementia. Alzheimer’s Association. (accessed March 17, 2022).
  7. What is Dementia? Alzheimer’s Association.  (accessed March 17, 2022).
  8. Dementia n.d. World Health Organisation. (accessed March 17, 2022).
  9. Huntington’s Disease Information Page | National Institute of Neurological Disorders and Stroke n.d.  (accessed March 17, 2022).
  10. Creutzfeldt-Jakob Disease Fact Sheet | National Institute of Neurological Disorders and Stroke n.d.  (accessed March 17, 2022).
  11. What Is Mental Illness? n.d. American Psychiatric Association. (accessed March 17, 2022).
  12. Kessler RC, Berglund P, Demler O, Jin R, Merikangas KR, Walters EE. Lifetime prevalence and age-of-onset distributions of DSM-IV disorders in the National Comorbidity Survey Replication. Arch Gen Psychiatry. 2005; 62(6):593–602.
  13. What Is Depression? n.d. American Psychiatric Association.  (accessed March 17, 2022).
  14. Six common depression types. Harvard Health 2017.  (accessed March 17, 2022).
  15. Byers AL, Yaffe K. Depression and Risk of Developing Dementia. Nat Rev Neurol 2011;7:323–31.
  16. Depression and dementia | Alzheimer’s Society n.d.  (accessed March 17, 2022).
  17. Hallucinations and dementia | Alzheimer’s Society n.d.  (accessed March 17, 2022).
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Joohee Uhm

Master of Science - MS, Global Health and Development, UCL (University College London)
Joohee an experienced program coordinator in multiple international development settings with a keen interest in community engagement and inclusion. With a strong affinity to work in the field to organizing effective liaison channels to ensure smoother operations of training exercises.

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