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Cognitive decline refers to a measurable reduction in one or more cognitive abilities — such as memory, attention, executive function, language, learning, judgment, and processing speed — from an individual’s previous level of functioning. Some degree of decline, particularly in processing speed and fluid abilities, is a normal feature of healthy aging and is referred to as age-related cognitive decline. When decline exceeds what is expected for a person’s age and education but does not interfere with independent daily functioning, it is classified as mild cognitive impairment (MCI) or, in DSM-5 terminology, mild neurocognitive disorder; when it is severe enough to interfere with independence in everyday activities, it is classified as major neurocognitive disorder (dementia). Cognitive decline can arise from a wide range of causes, including neurodegenerative disease, vascular and metabolic conditions, medication effects, and modifiable lifestyle and dietary factors.
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The Center for Nutritional Psychology. (2026). Cognitive Decline. In Encyclopedia of Nutritional Psychology. The Center for Nutritional Psychology.
https://www.nutritional-psychology.org/encyclopedia/cognitive-decline/Know a term that belongs in the Encyclopedia?
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