Is it dementia or depression?

With more than seven million people age 65 or older in the U.S. with dementia, and approximately 21 million adults having experienced a major depressive episode, you may know someone with one of these conditions.

Dementia refers to a group of conditions marked by loss of brain function across multiple areas, including memory, problem-solving and general thinking. Dementia is described as progressive, meaning it generally worsens over time.

Various diseases, such as Alzheimer's disease and vascular dementia, can be categorized within the general term dementia. There are other causes, too, including dementia from substance use disorders.

Major depressive disorder, commonly known as depression, is also an illness that can affect thinking. However, low or poor mood is traditionally the primary symptom.

“Because some symptoms of depression and dementia overlap, the two conditions can be mistaken for each other, especially in older adults,” says Dr. Paulette Cazares, principal investigator at the Sharp Neurocognitive Research Center.

The overlap between depression and dementia

Depression and dementia can feed off each other. “Many people with dementia or depression have difficulty socializing and can isolate, both of which can worsen their condition,” says Dr. Cazares.

She adds that chronic conditions, like diabetes and obesity — as well low levels of physical fitness —are risk factors for dementia. “Depression is also a risk factor, although having depression doesn’t directly cause dementia,” Dr. Cazares says.

Treatment for these conditions and even small, healthy changes to one’s lifestyle, such as decreased alcohol use or increased walking each week, can help ease symptoms.

Differences between depression and dementia

While depression can occur at all ages across the lifespan, dementia is quite rare in adults younger than 65. Sleep difficulties and poor appetite are common symptoms of depression, but these don’t often show up in dementia until much later stages.

Depression occurs in episodes and can be treated to what providers and patients call remission, which refers to a state of zero or near-zero symptoms. Dementia is a progressive condition that can be stabilized, but it cannot be reversed.

Dr. Cazares shares additional key differences between dementia and depression:

When to seek care

If someone is starting to struggle with living the life they once enjoyed, Dr. Cazares encourages a visit to the doctor, as many causes can be at play. Labs, cognitive assessments, brain imaging, as well as a discussion of lifestyle and family history, can all be helpful for a doctor to make an accurate diagnosis.

Whether it’s depression or dementia, Dr. Cazares says loved ones often notice changes in behavior earlier than the person affected. Thus, they can be helpful motivators to seek care.

“No matter how old we are, we all deserve to live a quality life,” she says. “Seeking and receiving early treatment are important.”

Learn more about the Sharp Neurocognitive Research Center, which offers free memory screenings in English or Spanish for adults 55 years old or older.