Few health problems can prompt the kind of drastic repercussions of impaired cognitive functioning. Owing to age, disease, or other factors, compromised memory and thought processing can create new demands on family and caregivers.

According to the Alzheimer’s Association, more than 6 million Americans of all ages are living with Alzheimer’s; 1 in 3 seniors die having been diagnosed with some form of dementia or Alzheimer’s. But these conditions are not exactly the same. Here’s why.

Dementia is a term used to describe a decline in mental ability as a result of damaged brain cells that interferes with normal activities and self-care. A person’s memory, ability to reason, or other cognitive skills are affected. In a way, using the term dementia is like saying a person is feeling ill—it’s a nonspecific label that’s a syndrome, not a disease itself.

Dementia can be caused by a number of conditions, including vascular disease as a result of high blood pressure, Parkinson’s disease, or reversible conditions like thyroid issues or vitamin deficiencies. To diagnose dementia, a doctor will typically look for impairment or change in at least two of the following areas: disorientation, disorganization, language, mood, personality, and memory. In dementia, irritability or depression can appear before memory issues do.

The most common cause of dementia is Alzheimer’s disease, which accounts for up to 80 percent of dementia cases and is neurodegenerative, getting slowly and irreversibly worse over time. First identified by Dr. Alois Alzheimer in 1906, it may begin with memory problems and graduate to confusion along with problems swallowing or walking. Cells in the brain may be affected by beta-amyloid protein fragments and tau protein, known as “plaques and tangles,” which can interfere with how cells communicate with one another. Doctors begin to suspect Alzheimer’s if the impairment is gradual and continues to get worse.

Alzheimer’s is typically a diagnosis made after other possible causes of dementia have been eliminated. If saying a person has dementia is like saying a person is ill, then Alzheimer’s would be a specific cause of the illness.

It may not seem like an important distinction, but treatments for one type of dementia and Alzheimer’s can vary. Some might do well on an antidepressant, while others may benefit from a drug that improves cognitive ability.

There are few pharmaceutical treatments for Alzheimer’s, though research is ongoing. In June 2021, the Food and Drug Administration (FDA) approved the first drug for the disease in 18 years: Aduhelm, a drug given via infusion which reduces the beta-amyloid proteins that can damage cells. Experts are divided on the benefit of the medication, which some researchers believe needs to be studied more extensively before any conclusions about the result of clearing the plaque can be understood.

To sum up: A person with Alzheimer’s has dementia, but not everyone with dementia has Alzheimer’s. Some forgetfulness is expected with age, but if memory issues are interfering with your daily activities, it’s best to be evaluated by a physician.