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- Written by: Cassandra Williams, Health Editor
Reviewed by: A2ZHealthy Editorial Team
Last Updated: January 26, 2026
According to a recent study published in the acclaimed Journal of the American Medical Association, nearly 50 million people worldwide have dementia. By 2050, that number is anticipated to have increased threefold, reaching over 140 million.
To better understand dementia and learn how to recognize its signs in ourselves and our loved ones, we’ll look at the disease’s phases, causes, and symptoms in this blog post.
Dementia is a broad term that describes a decline in cognitive ability that is severe enough to interfere with a person’s daily activities. It is caused by physical changes in the brain and is a progressive, degenerative condition that affects memory, thinking, language, judgment, and behavior.
Alzheimer’s disease is a particular type of brain disease, but dementia is a broad phrase. It is characterized by dementia symptoms that progressively worsen over time. Early symptoms of Alzheimer’s disease frequently involve problems in memory, thinking, and reasoning abilities since the disease first affects the area of the brain connected to learning.
The most common cause of dementia is Alzheimer’s disease, which accounts for an estimated 60% to 80% of cases. Other recognized forms include vascular dementia, which can develop after reduced blood flow to the brain, often related to strokes or small vessel disease, and Lewy body dementia, a condition linked to the abnormal accumulation of protein deposits in brain cells. Each type of dementia affects thinking, memory, and behavior in different ways. Understanding these distinctions can help provide context when recognizing possible changes in cognitive function. Next, we will review the common signs and symptoms of dementia. Mayo Clinic. Dementia – Symptoms and causes.
Signs and symptoms of dementia
Despite there being different types of dementia, the symptoms are similar, and the most striking differences include its onset, progression, and causes.
Early symptoms of dementia include:
• Memory loss
• Difficulty finding the right words
• Language difficulties
The symptoms are initially mild and more likely confounded with forgetfulness and age-related memory decay. But as the disease progresses, individuals may experience more severe symptoms, such as:
• Confusion with time and place
• Difficulty with basic math and reasoning
• Problems with visual and spatial abilities
• Trouble recognizing people and objects.
It is important to note that these symptoms can vary from person to person, and some may experience more severe symptoms than others. Additionally, some may experience changes in behavior and mood, including agitation, delusions, and even hallucinations. It is also common for individuals with advanced dementia to have difficulty with activities of daily living, such as dressing, bathing, and eating. National Institute on Aging. What Is Dementia?
Alzheimer’s disease
Alzheimer’s disease is a devastating neurological disorder that affects millions of people around the world. It is the most common form of dementia, leading to a progressive decline in cognitive abilities and memory.
Causes of Alzheimer’s disease
The cause of Alzheimer’s disease is still unknown, but many factors are believed to contribute to its development.
• Age is the most common risk factor, with the risk of developing the disorder increasing with age.
• Genetics also plays a role, and some people are genetically predisposed to the disease.
• Additionally, environmental factors such as exposure to head trauma, certain infections, and a lack of mental stimulation may increase the risk of Alzheimer’s.
The exact mechanism of Alzheimer’s disease is largely unknown, but evidence suggests that a combination of genetic, environmental, and lifestyle factors are involved. Research has indicated that a brain build-up of a protein called amyloid-beta is a critical factor in developing this disease. This protein accumulates over time, damaging the nerve cells in the brain.
Stages of Alzheimer’s disease
Alzheimer’s disease typically follows a three-stage progression, beginning with mild cognitive impairment and progressing to moderate and severe stages.
• Early stage: In the mild stage, individuals may experience difficulty with memory, planning, organizing, and multitasking.
• Intermediate stage: As the disease progresses, they may experience further cognitive decline, including confusion, disorientation, and difficulty communicating.
• Advanced stage: In the severe stage, individuals may have difficulty recognizing family and friends and eventually become totally dependent on others for their care.
Vascular dementia
Vascular dementia is a type of cognitive decline caused by decreased blood flow to the brain. It is the second most common form of dementia, accounting for 10-20% of all cases. It is caused by damage to the brain’s blood vessels due to medical conditions such as stroke, heart attack, or hypertension. This damage can decrease the brain’s ability to process information and store and recall memories. Vascular dementia is a progressive condition that can significantly impact a person’s quality of life.
Causes of vascular dementia
The exact cause of vascular dementia is unknown, but several factors are thought to be involved. These include a history of stroke, hypertension, diabetes, heart attack, and other cardiovascular diseases. Other risk factors include smoking, high cholesterol, and poor dietary habits.
In addition, risk factors for developing vascular dementia include age, family history, and certain genetic conditions. More research is needed to understand the underlying mechanisms better, but treating and managing vascular dementia requires careful monitoring and management of risk factors, such as those mentioned above.
Stages of vascular dementia
The stages of Alzheimer’s disease are similar to those of vascular dementia, but the symptoms in each stage are slightly different:
• Early stage: The first stage is the mild stage, characterized by slight problems with memory, language, and problem-solving. During this stage, people may also experience confusion, difficulties with concentration, and changes in behavior depending on what area of the brain is affected.
• Intermediate stage: The second stage is the moderate stage, associated with further cognitive decline. People may experience memory problems, difficulty finding words, and difficulty performing daily activities.
• Advanced stage: The third stage is the severe stage, during which people experience significant memory loss, disorientation, and an inability to perform basic activities such as bathing or eating. At this point, they may also require round-the-clock care.
