Some conditions share symptoms with dementia. Here is a comparison between dementia, mild cognitive impairment, depression, and delirium:
Is It Dementia or Other Conditions?
Dementia and mild cognitive impairment are different conditions.
Mild Cognitive Impairment (MCI) is a disorder with a modest but noticeable and measurable decline in cognitive abilities including memory and thinking skills.
A person with MCI is still able to function at his/her usual level but is at an increased risk of developing dementia.
Unlike dementia, MCI does not impair a person’s ability to carry out simple routine tasks or lead a normal life.
Adapted from: SingHealth1
As both depression and dementia can share very similar symptoms such as isolation, a declining interest in hobbies, social withdrawal, and detachment, the two conditions can be easily confused. Severe depression can also sometimes cause a group of cognitive impairment symptoms known as pseudodementia, making it harder for one to articulate their feelings associated with depression.
Though research on the link between dementia and depression is still developing, many sources suggest that having symptoms of dementia in mid- or late life is associated with a higher risk of developing dementia.2 However, persons living with depression do not necessarily develop dementia.
Some key differences between dementia and depression are:3
• Onset, duration, and course: The onset of dementia is slow and insidious, with a progressive and irreversible deterioration; depressive episodes consist of mood changes that can last from two weeks to years, but are reversible.
• Mood: A depressed mood may be, but is not definitely present in early dementia; a depressed mood is definitely present in a person who experiences depression.
• Thinking: With dementia, there is often difficulty with word-finding and abstraction, but in depression, thinking is often intact, though the content of thought often has themes of helplessness and hopelessness.
Delirium refers to an abrupt change in the brain characterised by a fluctuation in the person’s level of consciousness, psychomotor disturbances, memory impairments, emotional changes, and altered cognition or perception, that occurs over hours or days. Risk factors include the development of a physical illness, sensory impairments, recent surgeries, and use of drugs or substances (either prescribed or illicit). Delirium is usually reversible.
Delirium does not necessarily occur with dementia, and persons who do not have dementia can encounter delirium too. Unlike delirium, dementia slowly progresses over years, does not disturb levels of consciousness, is permanent, and has fairly consistent signs and symptoms. The behaviour of persons living with dementia is also fairly consistent on a day-to-day basis.
- SingHealth. (n.d.) Mild Cognitive Impairment (MCI): Signs and Symptoms. HealthXchange.sg. Retrieved on 5 March, 2021, from https://www.healthxchange.sg/seniors/ageing-concerns/mild-cognitive-impairment-signs-symptoms
- Barnes, D. E., Yaffe, K., Byers, A. L., McCormick, M., Schaefer, C., & Whitmer, R. A. (2012). Midlife vs late-life depressive symptoms and risk of dementia: Differential effects for Alzheimer disease and vascular dementia. Archives of general psychiatry, 69(5), 493-498.
- Victoria State Government. (n.d.). Differential diagnosis – depression, delirium and dementia. health.vic. Retrieved April 28, 2021, from https://www2.health.vic.gov.au/hospitals-and-health-services/patient-care/older-people/cognition/diff-diagnosis
- Changi General Hospital. (2019, January 10). Delirium: Symptoms and Management. HealthHub. https://www.healthhub.sg/a-z/diseases-and-conditions/627/delirium
- Lim, S. C. (n.d.). Dementia and Delirium: Know the Difference. HealthXchange.sg. Retrieved on 24 March, 2021, from 1. https://www.healthxchange.sg/head-neck/brain-nervous-system/dementia-delirium-difference