Six Early Symptoms of Dementia That Appear Long Before Cognitive Decline

A diagnosis of dementia is most often associated with a decline in memory and thinking. However, some preliminary symptoms of impending dementia, unrelated to thinking, can appear years or even decades before the onset of thinking problems, writes The Washington Post.

Alzheimer's disease, which accounts for 60 to 80 percent of dementia cases, develops in three stages. The first stage can begin 15 to 20 years before noticeable changes in cognitive function. During this period, the brain gradually shrinks, and the misfolded proteins characteristic of the disease begin to accumulate—sticky beta-amyloid plaques in the brain and tau tangles in neurons.

This is followed by a stage of mild cognitive impairment: the person develops noticeable problems with memory and thinking, but generally retains the ability to function. This is followed by dementia, when several cognitive functions are impaired and the person loses the ability to live independently.

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Scientists believe that biological changes in the brain during the first two stages can cause emotional, sensory, and physical symptoms long before a possible diagnosis.

"A person can have many of these warning signs and still not have any cognitive symptoms," explained Timothy Chang, an associate professor of neurology at the University of California, Los Angeles.

Experts emphasize that the presence of early signs associated with an increased risk of Alzheimer's disease does not necessarily mean that dementia will develop. About 45 percent of cases can be prevented through lifestyle changes.

Here are six early symptoms that are common in people who are later diagnosed with Alzheimer's disease.

Depression and anxiety that develop later in life

Depression is considered a risk factor for dementia. A 2023 study of over 1,4 million Danish adults found that the risk of dementia in people diagnosed with depression was 2,4 times higher.

However, depression and anxiety that occur later in life (around 55–60 years) can also be a signal that unfavorable changes are occurring in the body.

"Changes in the brain's neural networks in the early stages of dementia are thought to also affect mental health, so such changes could be seen as a signal of possible early brain dysfunction," Chang said.

Research has shown that such mood disorders can accelerate the development of dementia.

Increased apathy, irritability, or agitation

Neuropsychiatric symptoms such as irritability and hyperarousal are common in Alzheimer's disease and may occur even before cognitive decline.

A 2017 study of nearly 1400 people found that mood symptoms were observed in about 31 percent of older adults without cognitive impairment, 47 percent of those at increased risk of dementia, and 54 percent of those with mild cognitive impairment.

According to Adam Turnbull, a professor of psychiatry and behavioral sciences at Stanford University and author of a recent paper on emotion dysregulation in preclinical Alzheimer's disease, 50 to 60 percent of people with biomarkers for the disease have at least one neuropsychiatric symptom.

"If you're constantly feeling irritated, angry, lashing out at others, and your relationships are increasingly becoming conflictual and negative, it's worth seeking help from a mental health professional, such as a geriatric psychiatrist," advises Turnbull.

Sleep problems

Quality sleep has a protective function, so its disruption can be a sign of trouble.

Sleep apnea and other disorders, including excessive daytime sleepiness, restless legs syndrome, and circadian rhythm disorders, are associated with an increased risk of dementia, according to a 2025 meta-analysis of 39 studies.

Insomnia or reduced nighttime sleep may also precede dementia. One study of over 4400 older adults without cognitive impairment found that less nighttime sleep or, conversely, longer daytime naps were associated with increased accumulation of beta-amyloid in the brain—a biological marker of Alzheimer's disease.

At the same time, each additional hour of sleep at night was associated with lower levels of beta-amyloid. Research shows that during sleep, the brain can clear waste products, including beta-amyloid.

A short nap during the day shouldn't be cause for alarm. However, if a person sleeps a lot during the day and sleeps poorly at night, this may be cause for concern, Turnbull noted.

Loss of smell

The ability to distinguish smells is closely linked to brain health, and its loss is often one of the early signs of neurodegenerative diseases, including Alzheimer's and Parkinson's. About 85 percent of people in the early stages of Alzheimer's experience olfactory problems.

The olfactory system is directly connected to the brain. Unlike other senses, such as hearing and vision, odor signals travel more quickly to the cerebral cortex and are then connected to areas responsible for memory, emotion, and cognitive functions, including the hippocampus and amygdala.

Interestingly, the olfactory nerve is capable of regeneration, and the ability to distinguish odors can be trained. There is even preliminary evidence that such training can improve cognitive function even in people with a normal sense of smell.

Slowing down walking

Changes such as a slower gait, shorter strides, or a wider stance were long thought to be a natural part of aging. However, research shows that they may precede cognitive decline and other neurological problems.

A 2024 study of more than 1300 healthy people over 65 found that walking ability, including speed and the ability to turn 360 degrees, declines ten years before cognitive decline.

Decreased grip strength

Grip strength is closely linked to overall health as we age and may be a more accurate indicator of lifespan than blood pressure.

Decreased grip strength is also associated with poorer cognitive health. One recent study, which included over 190 adults, found that every 5 kilogram decrease in grip strength was associated with a 20 percent increased risk of dementia in men and a 12 percent increased risk in women. Furthermore, a weaker grip was associated with poorer performance on problem-solving and memory tasks.

Grip strength is one of the indicators doctors use to assess physical frailty, along with gait characteristics. In medical terms, physical frailty signifies increased vulnerability to disease and injury. It is both a risk factor for dementia and a possible early sign, which can appear approximately ten years before the onset of cognitive symptoms.

When to see a doctor

"If you're an older person and notice these symptoms, don't immediately panic and think you have dementia. It's quite possible they're not related to neurological disorders," Turnbull noted.

However, if you experience concerns about memory or thinking, especially if accompanied by the symptoms listed above, it's important to consult a doctor. Modern diagnostic methods, including PET scanning, lumbar puncture, and new blood tests, make it possible to detect Alzheimer's biomarkers in the early stages, which can speed up treatment.

"It's helpful to get checked out and have your doctor evaluate whether there's cause for concern or not," Chang emphasized.

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How to reduce the risk of dementia

The risk of dementia is partly determined by genetics, but there are also many ways to reduce it.

Last year, the POINTER clinical trial in the US found that a combination of physical activity, healthy eating, social engagement, and brain training helps improve cognitive function in older adults at risk of cognitive decline or dementia.

Other studies suggest that avoiding alcohol, getting regular vaccinations, and protecting your hearing may also help preserve cognitive function.

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