Six Early Symptoms of Dementia That Appear Long Before Cognitive Decline

Memory loss and thinking problems are what most people associate with a dementia diagnosis. However, some early warning signs of impending dementia, ones that have nothing to do with thinking, can appear years or even decades before cognitive issues begin, 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 in volume, and the misfolded proteins characteristic of the disease begin to accumulate, sticky beta-amyloid plaques in the brain and tangles of tau protein inside neurons.

Next comes the stage of mild cognitive impairment: a person develops noticeable problems with memory and thinking but is still generally able to function. After that comes the dementia stage, when multiple cognitive functions are affected and the person loses the ability to live independently.

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

"A person can have many of these precursors and yet show no cognitive symptoms at all," explained Timothy Chang, assistant professor of neurology at the University of California, Los Angeles.

At the same time, specialists emphasize: having early signs associated with an increased risk of Alzheimer's does not mean that dementia will definitely develop. About 45 percent of cases can be prevented through lifestyle changes.

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

Depression and Anxiety That Emerge Later in Life

Depression is considered a risk factor for dementia. A 2023 study covering more than 1.4 million Danish adults showed that the risk of dementia in people diagnosed with depression was 2.4 times higher.

However, depression and anxiety that emerge later in life (around age 55 to 60) may also be a signal that unfavorable changes are happening in the body.

"It is thought that changes in the brain's neural networks during the early stages of dementia also affect mental state, so such changes can be seen as a signal of possible early brain dysfunction," Chang said.

Studies have shown that such mood disorders can accelerate the development of dementia.

Increased Apathy, Irritability, or Agitation

Neuropsychiatric symptoms such as irritability and increased agitation are common in Alzheimer's disease and can appear even before cognitive decline sets in.

In a 2017 study involving about 1,400 people, it was found that mood disturbance symptoms were observed in approximately 31 percent of older adults without cognitive impairment, 47 percent of those at higher risk for dementia, and 54 percent of those with mild cognitive impairment.

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

"If you constantly feel irritable, angry, lash out at those around you, and your relationships increasingly turn into conflicts and take on a negative tone, it's worth seeking help from a mental health professional, such as a geriatric psychiatrist," Turnbull advises.

Sleep Problems

Quality sleep serves a protective function, so disruptions can be a sign of underlying problems.

Sleep apnea and other disorders, including excessive daytime sleepiness, restless legs syndrome, and circadian rhythm disturbances — are associated with an increased risk of dementia. This was shown in a 2025 meta-analysis covering 39 studies.

Insomnia or reduced nighttime sleep can also precede dementia. One study of more than 4,400 older adults without cognitive impairment found that less nighttime sleep or, conversely, more daytime napping were associated with greater accumulation of beta-amyloid in the brain a biological marker of Alzheimer's disease.

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

A short daytime nap shouldn't cause concern. However, if a person sleeps a lot during the day and sleeps poorly at night, that might be a reason to pay attention, Turnbull noted.

Loss of Smell

The ability to distinguish smells is closely linked to brain health, and its loss often becomes 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 smell problems.

The olfactory system is directly connected to the brain. Unlike other senses, such as hearing and vision, smell signals reach the cerebral cortex more quickly 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 smells can be trained. There is even preliminary evidence that such training can improve cognitive function even in people with normal smell perception.

Slowing Gait

For a long time, changes such as slower walking, shorter steps, or a wider stance were considered a normal part of aging. However, research shows that they may precede cognitive decline and other neurological problems.

A 2024 study involving more than 1,300 healthy people over 65 found that walking ability, including speed and the ability to turn 360 degrees, deteriorates ten years before cognitive decline begins.

Decreased Grip Strength

Grip strength is closely related to overall health during aging and may be a more accurate predictor of lifespan than blood pressure.

Decreased grip strength is also linked to declining cognitive health. In a recent study covering more than 190,000 adults, it was found that every 5-kilogram decrease in grip strength was associated with a 20 percent increase in dementia risk for men and a 12 percent increase for women. Additionally, weaker grip correlated 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 means increased vulnerability to illness and injury. It is both a risk factor for dementia and a possible early warning sign that may appear about ten years before cognitive symptoms begin.

When to See a Doctor

"If you're an older adult and notice such symptoms in yourself, don't panic and immediately think about dementia. It's quite possible they're not related to neurological problems," Turnbull noted.

However, if you're concerned about your memory or thinking, especially if it's accompanied by the symptoms listed above, it's important to see a doctor. Modern diagnostic methods, including PET scans, spinal taps, and new blood tests, can detect Alzheimer's biomarkers in the early stages, which may speed up the start of treatment.

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