Sept. 5, 2025 – A persistent brain fog may make you uneasy as you get older. Is it normal or is it dementia?
Don't jump to that conclusion. A visit to your regular doctor may reveal an overlooked cause: late-life depression.
News about dementia is everywhere these days and can unleash upsetting thoughts for older adults.
But what you may not know: Depression symptoms and cognitive problems can appear similar, said Sonja Blum, MD, PhD, an expert in cognitive aging and memory disorders at Weill Cornell Medicine in New York City.
Blum estimates that 30% to 50% of her older patients have depression, usually with anxiety. But most of her patients don't mention depression or anxiety symptoms because they're eager to talk about their memory problems. Patients often tell her they think it's normal "to have these mood symptoms in their situation or because of the cognitive symptoms," she said.
"The tricky part is that, given the overlap between the symptoms of depression and mild cognitive impairment of memory disorders, you have a chicken-and-the egg kind of thing. Sometimes the cognitive deficits can be from the anxiety and depression, or from the beginning of Alzheimer's disease."
Nearly all people 65 and older begin to have a decline in mental skills, also called cognitive impairment. The overlap of depression and cognitive problems is high: Nearly 1 in 20 older adults have major depression, with many more (up to 50% of people in nursing homes) having less severe depression symptoms.
Among people diagnosed with late-life depression, up to half have been found to also meet criteria for mild cognitive impairment.
A few basic questions and a checklist of symptoms can help you assess cognitive changes amid depression and help you ask the right questions during a checkup so depression doesn't get missed.
Gauging Your Symptoms: Persistent or Relentless?
Older people with cognitive problems due to depression will often report brain fog or brain fuzziness, Blum said – but then perform well on cognitive recall tests, like remembering a list of words, even if they need a clue or two.
People with early Alzheimer's or another type of dementia don't usually report mood problems because a part of the disease that scientists call anosognosia impairs their own insight. They may similarly struggle to recall some words during testing, but getting clues doesn't help, as it does for people whose cognition is affected by depression.
When cognitive issues stem from depression, they typically involve problems with executive function (like planning and prioritizing tasks), slowed processing speed, attention, and some memory issues, Blum said. Even though depression can get worse, the brain fog usually doesn't – it's "persistent, but it doesn't seem to have a kind of relentless decline that we usually see in degenerative disease in the brain." A doctor may ask you to describe your brain fog.
Another consideration: Is your depression new, or has it affected you on and off since you were younger?
"Depression, especially starting in midlife or earlier, has been an established risk factor for dementia," said Antonio L. Teixeira, MD, PhD, a geriatric neuropsychiatrist at the Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases at the University of Texas Health Science Center at San Antonio. A history of depression may warrant further testing for dementia.
How to Help Your Doctor Accurately Diagnose You
Should you see a neurologist or a psychiatrist to talk about cognitive problems that may be due to depression? Neither – your first stop should be your primary care provider, said Eric Lenze, MD, chair of the Psychiatry Department and a professor at Washington University School of Medicine in St. Louis.
Here's what to ask your primary care doctor:
- Do you think my cognitive function needs further assessment?
- Will you look at my medications and tell me if any of them are causing cognitive problems?
- Do you think there's anything treatable here, like depression?
"Most doctors are not well-trained to understand the differentiation between cognitive complaints," said Lenze, who is a geriatric psychiatrist.
It's one thing to say, "Hey, I don't think my brain works as well as it used to," Lenze said. Actual cognitive impairment is more like, "OK, this person can't shop independently anymore, or they can't drive independently anymore, or they shouldn't be living independently anymore because of their brain, not because of physical frailty." That, said Lenze, is impairment.
Don't assume your primary care doctor will look at your meds – bring a list with you and show it to them. "They should be able to look down your list of medications and say, 'Oh my, you're taking a bladder medication that causes memory impairment. Let's take you off that.' "
Ask about depression specifically – older adults' depressive symptoms often are nuanced. They can include:
- Low mood, which typically isn't sadness, but feeling "blah"
- Lack of interest in things you used to enjoy
- More physical complaints, like pain
- Negative thoughts about yourself or the world, such as feeling like you are a burden on people, or feeling guilty, regretful, or hopeless
What about thinking about your own death? That's often normal, but thoughts such as "would it be better if I wasn't alive" should be a red flag and shared with your health care provider.
When to See a Specialist
Feel like skipping your primary care doctor and going straight to a neurologist or a psychiatrist? That may affect your diagnosis, said Teixeira, who works in both neurology- and psychiatry-focused clinics.
"If an older person goes to a psychiatrist with depressive and cognitive complaints, he'll probably get the diagnosis of depression, and the diagnosis of mild cognitive impairment [MCI] may be overlooked," he said. "Conversely, if the patient goes through a neurologist, he will probably get the MCI diagnosis, and depression may be overlooked."
Blum, who is a neurologist, said neuropsychological testing offers important benefits.
"If there are any cognitive changes associated with the mood, then it is advisable to also see a neurologist if possible to help disentangle whether there is something going on that is the beginning of a dementia that may require different treatment," she said.
One reason to visit a psychiatrist: Wait times for neurology appointments can be months, Lenze warned. And Teixeira said that depression can potentially skew neuropsychological testing results.
"Usually, when you go to the neurologist, you're not going to complain about depression. You're going to complain about the cognitive symptoms. And many times, this depression is kind of hidden or not really acknowledged," he said.
Untreated depression that affects cognition can skew test results "because many times, depressed people are not engaged in the tests and are not fully attentive, and this might overestimate, in a negative way, their performance," Teixeira said.
Even anxiety over a potential dementia diagnosis (a family history can spike worries) can also affect test results, he said.
Treatment Options
Medication is still the mainstay treatment for depression, often combined with psychotherapy, Lenze said, though people with serious cognitive impairment may be unable to fully take part in the therapy.
Remember, antidepressants take at least four weeks to work (and ideally need eight to 12 weeks), and be sure to take them as directed. If there isn't good improvement after 12 weeks, Lenze said you should ask your doctor to try a different antidepressant medication.
Insufficient dosage and not sticking with the meds long enough are usually the reasons why antidepressants don't work, Lenze said. There's a 50% likelihood that, taken correctly, an antidepressant will send depression into remission, he said. And if the first medication you try doesn't help, you get another 50% likelihood of remission when trying the second medication.
Combining medication with other therapies and lifestyle changes often helps, such as:
- Psychotherapy, including a kind called reminiscence therapy, "taps into reconnecting with positive memories and fostering emotional resilience. It works very well for late-life depression," Blum said.
- Aerobic exercise increases blood flow to the brain, which helps with its adaptability (neuroplasticity) and with producing new neurons (neurogenesis), Blum said.
- Quitting alcohol boosts brain health. "Increasingly, older adults who are depressed are drinking alcohol. Stop drinking, and your brain will improve. Your depression will get easier to treat," Lenze said.
For people who have serious cognitive problems – or mild cognitive impairment – due to depression, other treatments may be tried, including electroconvulsive shock therapy (ECT), ketamine, or transcranial magnetic stimulation.
One woman Lenze treated had been diagnosed with dementia by a neurologist in her late 60s, which had come on very quickly. It turned out she had psychosis from depression. When she got ECT, she was cured, and she doesn't even remember that period of her life. Such a situation is very rare, Lenze said, but important to consider as a possibility.
Until recently, having serious cognitive problems amid depression was referred to as pseudodementia, although the term has fallen out of favor because experts say it doesn't adequately address what's happening beneath the surface.
Folks with late-life depression may have trouble mustering the motivation to seek treatment, Lenze said. Don't hesitate, he urged: Treatment can resolve not just cognitive problems but also other depression symptoms.
"The patients who do the best have someone helping them – dragging them to appointments and acting as an informant. The patient will say, 'Yeah, I guess I feel fine.' And then there's the spouse saying, 'Wait a second, just yesterday you were telling me you were having suicidal thoughts and you laid in bed all day,' " Lenze said.
Having a family member or helper to ensure you take your medication is particularly important, he said.
"Depression itself saps your motivation," Lenze said. "And just as badly, it instills in you a lot of pessimism and self-doubt that can really interfere with getting treatment and sticking with it."
The national Suicide and Crisis Lifeline provides help 24 hours a day, seven days a week. You can reach it by calling or texting 988, or chatting online.
