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What Are Dementia and Alzheimer’s Disease?

Dementia is a collective term used to describe neurodegenerative disorders of the brain that affect cognition. It is estimated that over 55 million people around the world have dementia. Alzheimer’s disease is the most common type of dementia (60-80% of cases) and affects 6.7 million Americans, according to the Alzheimers's Association. In people with dementia, the impairment in cognition is different from the memory problems associated with normal aging. Dementia can impair their ability to take care of themselves and their daily affairs.

In a person with dementia, the neurons in the regions of the brain that affect cognition progressively get damaged. Dementia is a clinical diagnosis made in individuals with a significant decline from their baseline level of cognitive performance. The decline can occur in one or more cognitive domains, including:

  • Memory, including the ability to remember recent events and conversations.
  • Learning new information and applying it.
  • Ability to sustain attention on complex tasks.
  • Language, including naming, speaking without grammatical errors and with appropriate use of words.
  • Movement-related skills, including hand-eye coordination, body-eye coordination, and visual-auditory skills.
  • Ability to focus attention, plan, organize and coordinate multiple tasks.
  • Ability to perceive, understand, and judge others and one’s social behavior.

The severity of the cognitive impairment can be quantified through a neuropsychological assessment or a clinical assessment. For a diagnosis of dementia, a person’s cognitive issues should be severe enough to affect their ability to perform their daily activities independently. This includes their ability to manage their finances and medications, dress appropriately, and maintain hygiene. The cognitive impairment should not be the result of another psychiatric disorder like depression or schizophrenia, or medical conditions like delirium (a temporary state of confusion occurring over a short time due to underlying medical conditions, medications, substances, or toxins).

There are different types and causes of dementia. The most common types of dementia are:

  • Alzheimer’s disease: the most common type of dementia. Alzheimer’s disease usually begins with lapses in memory for recent events, conversations, names, or faces.
  • Vascular dementia: the second most common type of dementia. This type of dementia is caused by strokes or mini-strokes (also known as transient ischemic attacks). Each stroke or mini-stroke can cause problems in the blood supply of the brain. Individuals with vascular dementia have a progressive decline in cognition with each stroke or mini-stroke. The symptoms depend on the area of the brain being affected.
  • Dementia with Lewy bodies: in individuals who have dementia with Lewy bodies, the main symptoms include hallucinations; sleep disturbances like nightmares; appearing sleepy or tired; and trouble with movements or balance like falls, tremors, slow movements, and difficulties in walking. Problems with memory usually occur later in the progression of the disease compared to Alzheimer's disease.
  • Frontotemporal dementia: in frontotemporal dementia, individuals can experience personality changes (such as lack of interest or emotions, impulsive anger) and difficulties in organizing and planning daily activities like going to work and paying bills. They can also struggle with language, like difficulty naming things, making grammatical errors, using inappropriate words, and maintaining fluency of speech. Problems with memory usually occur later in the progression of the disease compared to Alzheimer's disease.

Individuals can have dementia caused by more than one factor. This is called mixed dementia. Dementia can also be caused by other medical conditions, including traumatic brain injury, use of alcohol and other substances, HIV infection, Parkinson’s disease, and Huntington’s disease.

In the initial stages of dementia, individuals may be able to work, drive, cook, and participate in their other daily activities with the help of friends and family. The progression of dementia and the abilities affected varies among individuals. As the disease progresses, they become increasingly dependent on their friends and family members to take care of their daily needs, like paying bills, buying groceries, and personal care, including bathing and dressing. They can also experience changes in mood, anxiety, paranoia, hallucinations, agitation, inappropriate sexual behaviors, and sleep disturbances. Individuals may wander from home and get lost or make mistakes while driving or cooking. This can cause significant concern for their safety. As the disease progresses to other parts of the brain, individuals with dementia can have problems with balance, falls, and swallowing. They may also eventually become bed-bound, requiring around-the-clock care.


Currently, there is no treatment that can reverse the disease process of dementia. The U.S. Food and Drug Administration (FDA) has approved medications to slow down the progression of Alzheimer’s disease (but not other types of dementia). Some of these medications belong to the class of medications called cholinesterase inhibitors, which are prescribed for mild to moderate Alzheimer’s disease [Aricept® (donepezil), Exelon® (rivastigmine) and Razadyne® (galantamine)]. One medication, Namenda® (memantine), has been approved by the U.S. FDA for treating moderate to severe Alzheimer's disease. In 2021, Aduhelm® (aducanumab) was approved by the U.S. FDA for treating Alzheimer's disease. Several new medications are also being studied to target various processes related to dementia with the goal of one day developing medications that can stop or slow down the cognitive decline of dementia.

Maintaining a healthy lifestyle can help prevent dementia from getting worse. Healthy lifestyle choices can include eating a balanced diet; being physically, socially, and mentally active; stopping smoking; cutting down alcohol consumption; getting regular health check-ups; and getting treatment for heart disease, hypertension, and diabetes.

Individuals with dementia can also have related conditions like depression, anxiety, agitation, and psychosis. Primary care providers or mental health providers can help manage these conditions with psychiatric medications, non-pharmacological interventions (such as addressing the cause of distress in the patient), or making lifestyle changes (like maintaining an appropriate sleep-wake cycle). Behavioral therapists who have specialized in the care of dementia can use therapies like reminiscence therapy, validation therapy, reality orientation, and cognitive stimulation therapy to alleviate distress and related behaviors, provide comfort, and avoid boredom or loneliness.

Individuals with dementia may have difficulty identifying or explaining their needs. Recognizing and addressing their needs (e.g., pain, hunger, constipation, infections, skin rash, ingrowing nails, full bladder, and appropriate room temperature) can help an individual become comfortable and decrease the risk of behavioral problems. A calm and non-stimulating environment can be helpful, especially for sleeping at night. When the individual is anxious or agitated, redirecting their attention can be helpful. Instructions should be provided in a simple manner and broken down at each step as individuals might have difficulty comprehending complex instructions. It is best to avoid being argumentative or confrontational with individuals with dementia, as they might not remember or understand the issues.

As the disease progresses in severity, the medications used to treat dementia or related behavior problems can become less effective. After discussing the risks versus benefits of the medications with the treating clinician, they can be discontinued to reduce the burden of taking inappropriate and unnecessary medications.

Caregiver Stress

Caring for individuals with dementia can be very stressful for family and friends, especially as the severity of dementia progresses and caregivers spend more effort and time caring for the individuals. Caregivers can struggle with accepting the severity of dementia or become angry and frustrated. As caregiving takes more time and energy, the caregiver can become socially isolated and lonely. They may experience anxiety, depression, and sleeplessness as they worry about the care of the individual with dementia and their future. The chronic stress of caregiving can also have a toll on the physical health of caregivers.

It’s important for caregivers to take care of themselves and to seek help when needed. If possible, caregivers should find time in the day for themselves to pursue activities that they enjoy, relax, and exercise. They should ask for help from family and friends to take turns in caring for the individual with dementia. Respite care or adult day care centers can also be considered (see the U.S. Administration on Aging’s Eldercare Locator). Caregivers should also try to not take problematic behaviors of individuals with dementia personally, as they are symptoms of the disease.

Caregivers should consider psychotherapy/counseling or see their mental health provider if they feel anxious or depressed about caring for their loved ones. Attending caregiver support groups for individuals with dementia can also be helpful. Information about caregiver support groups and other caregiver resources can be obtained from local chapters of the Alzheimer’s Association.

If the care for the individual with dementia is beyond the caregiver’s capabilities, long-term care facilities like assisted living facilities or memory care centers should be considered as they have nursing staff skilled in the care of individuals with dementia.

Physician Review

Badr Ratnakaran, M.D.

April 2023

Medical leadership for mind, brain and body.

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