I Thought It Was Early Dementia. It Was Perimenopause. Why These Symptoms Are So Easy to Misdiagnose.

I started to think I was developing dementia sometime in my mid-forties.

It was not one dramatic moment. It was recipes. I have cooked my whole life, and suddenly I could not follow one. I would misread the amount of an ingredient, or read it correctly and use the wrong one anyway. I would leave out an ingredient entirely. I would skip a step and only realize it twenty minutes later when the texture was wrong.

I put three minutes on the microwave instead of thirty seconds, walked away, and came back to a mess. More than once.

I would read a paragraph in a book or an article, get to the end of it, and understand nothing. So I would read it again. And again. And on the third pass I still could not tell you what it said.

Here is the thing I want to be careful about, because it matters. Every one of those things happens to everybody. Everyone misreads a recipe. Everyone rereads a paragraph. I had done all of it occasionally my whole adult life, the way we all do.

What changed was the frequency. It went from a few times a year to a few times a day. That shift, from occasional to constant, is what turned it from an annoyance into something I was genuinely frightened by.

It was perimenopause. Hormone therapy brought my mind back.

But I want to be honest about something, and it is the reason I am writing this article instead of a tidy one about brain fog. It could easily have been something else. Those exact symptoms belong to at least a dozen different conditions. If I had assumed hormones and stopped looking, and it had been my thyroid, or my B12, or something worse, I would have lost years to a confident wrong answer.

I know how that goes, because it happened to me once, and that time it was cancer.

The line between a bad day and a pattern

The hardest part of midlife symptoms is that every single one of them is deniable in isolation.

You forgot a name. You are tired. You have been under stress. Your knees ache, but you are not twenty-five anymore. Each individual instance has an easy explanation available, and most of the time the easy explanation is even true.

So how do you know when it is something?

For me, the answer turned out to be frequency, not severity. Nothing I was experiencing was severe. I never got lost driving somewhere familiar. I never forgot a person’s name permanently. What happened was that a thing which used to occur twice a year started occurring twice a day.

That is the test I would offer anyone. Not “is this dramatic enough to mention?” but “has the rate changed?” A symptom that used to be rare and is now routine has crossed a line, even if no single episode is impressive on its own.

The second test is interference. Is it changing what you do? I started writing things down that I never used to write down. I started rereading emails before sending them in a way I never had. When you have begun quietly building workarounds for yourself, you have already decided something is wrong. You just have not said it out loud yet.

What it turned out to be

In my case, the cause was falling estrogen, and the mechanism is well documented.

Estrogen is not only a reproductive hormone. It acts throughout the brain, and it has a particular role in the prefrontal cortex, the region that handles working memory, attention, and executive function. That is the part of your brain that holds a recipe in place while you execute it, tracks that you have already added the salt, and keeps a paragraph’s first sentence available while you read the third.

Estrogen supports dopamine signaling in that region. When estrogen falls and fluctuates the way it does in perimenopause, dopamine signaling in the prefrontal cortex is affected, and the functions that depend on it get less reliable.

Which is a technical way of saying: the thing I experienced as losing my mind was a measurable change in brain chemistry, in a specific region, for a specific reason.

Roughly 40 to 60 percent of women report cognitive symptoms during the menopause transition. I was not unusual. I was typical, and terrified, and had no idea the two things could both be true.

Hormone therapy resolved it for me. That is not a promise that it will for you, and it is worth saying clearly that it does not resolve it for everyone. Which brings me to the actual point of this article.

The conditions that share these exact symptoms

Here is what I did not appreciate at the time. “Brain fog, fatigue, low mood, hair loss, and joint pain in a woman in her forties” is not a description that points anywhere in particular. It is a description that points almost everywhere.

Look at that table and notice how much overlap there is in the middle column. Fatigue appears in nearly every row. Brain fog appears in most of them. Hair loss shows up in four.

This is the thing I most want you to walk away with. A symptom is not a diagnosis, and neither is your age. Being 45 makes perimenopause likely. It does not make it the answer, and it does not make your thyroid immune.

The other direction matters just as much. Some women get told for years that everything is their thyroid, or their stress, or their weight, when it is actually perimenopause. The error runs both ways. What is dangerous is not which label gets applied. It is applying a label confidently without checking.

The ADHD overlap almost nobody raises

I want to spend a moment on this one because it is a genuine gap, and because a reader whose fog does not clear on hormone therapy needs to know it exists.

Let me be clear about my own boundary first: I do not have an ADHD diagnosis, and I do not believe I have ADHD. My fog resolved with hormone therapy, which is a fairly strong indication of what was driving it in my case. Everything in this section is reporting, not lived experience.

A 2026 narrative review in Drugs & Aging by Wynchank and Kooij looked at the pharmacological management of ADHD in women across perimenopause, menopause, and after. The review notes that ADHD in women is frequently underdiagnosed and undertreated, particularly in midlife, when the hormonal changes of perimenopause can worsen or unmask symptoms that were always there.

The reason this happens is the same mechanism I described above. ADHD involves dopamine signaling in the prefrontal cortex. Estrogen supports dopamine signaling in the prefrontal cortex. When estrogen falls, a woman who had mild, manageable, never-diagnosed ADHD can lose the compensation she had been running on for forty years.

The review also names the diagnostic problem directly: the symptom lists overlap so heavily that telling the two apart is genuinely difficult, and there are no randomized controlled trials of ADHD medication specific to the perimenopausal population. So this is an area where the evidence is thin and the clinical guidance is thinner.

There is stronger data on how the two interact. A population-based cohort study published in European Psychiatry in 2025 compared 535 women with ADHD to 4,857 women without, all aged 35 to 55. Women with ADHD had higher total perimenopausal symptom scores (18.0 versus 13.0). Severe symptoms were far more common in the ADHD group: 54.2 percent versus 30.1 percent. And the difference was largest in the youngest group, women aged 35 to 39, which the authors read as evidence of an earlier onset of perimenopause in women with ADHD.

You may also see a figure circulating that 43 percent of women with ADHD are diagnosed for the first time in their forties. I looked for that number in the research and could not substantiate it. What I did find is an ADDitude magazine reader survey of more than 1,500 women, which reported an average age at diagnosis of 43 and found that 83 percent of respondents experienced some ADHD symptoms for the first time during perimenopause or menopause. That is a self-selected survey of a magazine’s readers, not a population sample, and it should be read that way. The 43 appears to be an average age that got repeated as a percentage somewhere along the line.

I am spelling that out rather than quietly dropping the number because how a statistic travels is part of the story here. Numbers get garbled, then repeated, then cited. It is worth asking where a figure came from before you take it into an exam room.

The practical point stands regardless of the statistics: if your brain fog does not lift when your other menopause symptoms do, ADHD is a question worth asking, and almost no one will ask it for you.

A story about cramps

I want to tell you about a time I was given a confident wrong answer, because it is the clearest example I have of why any of this matters.

I had cramping. It felt like mild menstrual cramps, nothing dramatic, nothing that doubled me over. What was strange about it was that it did not stop. It was constant, every day, for two months.

The first doctor I saw told me it was menstrual cramps and that I should pick up a pain reliever at the store.

That was a reasonable-sounding answer. It fit the symptom. It fit my age and my sex. If I had accepted it, nobody would have called it negligence.

But I knew it was not that. I had had menstrual cramps for thirty years. I knew what they felt like, and I knew they did not run for two months without stopping. So I took the initiative myself and went to see other specialists.

I was diagnosed with stage 2 colon cancer.

I am not telling you this to frighten anyone about cramping. Cramping is usually nothing serious, and I am not suggesting otherwise. I am telling you because the structure of that experience is exactly the structure of the perimenopause problem, just with much higher stakes.

A common symptom. An obvious explanation that fit my demographic profile. A doctor who applied the obvious explanation instead of asking what else it could be. And a patient who happened to know her own baseline well enough to say no.

This is a documented pattern, not just my bad luck. Research on colorectal cancer in younger adults has found that most patients are initially misdiagnosed. In one survey of young-onset patients, about 75 percent saw at least two physicians before getting the correct diagnosis, and roughly 20 percent saw four or more. Patients who saw three or more doctors before diagnosis were more likely to be diagnosed at an advanced stage. Researchers describing this pattern point to physicians attributing symptoms to more common benign conditions and not investigating further.

The delay is not neutral. In colorectal cancer, stage at diagnosis is one of the strongest predictors of outcome, and every doctor you have to see before someone takes you seriously is time.

I got a stage 2 diagnosis instead of something later because I did not accept the first answer. That is the whole reason I feel strongly enough about this to write it down.

Why misdiagnosis happens (and why it is usually not malice)

I do not think most doctors are dismissive people. I think the system they work in produces dismissive outcomes, and it helps to understand why, because it changes how you approach the appointment.

The appointment is short. A typical primary care visit runs fifteen to twenty minutes. If you bring six symptoms, there is not time to work through six differentials. The most common explanation gets applied because it is usually right and there is no time to be thorough about the exceptions.

The training gap is real. In a national survey of ob-gyn residency programs, only 31.3 percent had a menopause curriculum. In a survey of residents, just 6.8 percent felt adequately prepared to manage menopause. If specialists in women’s health were largely not taught this, your general practitioner very likely was not either.

Common things are common. Doctors are trained to think this way, and it is correct almost all the time. The problem is that it works against you specifically when you are the exception, and there is no way to know in advance whether you are.

“You are at that age” is a conversation stopper. Once a symptom in a woman over forty gets attributed to hormones, the search tends to end. It is the diagnostic equivalent of a shrug, and it can bury a thyroid problem, an anemia, or something worse underneath a label that sounds plausible.

None of this means the doctor is your adversary. It means you have to bring information they cannot get in fifteen minutes, and you have to be willing to ask one more question than feels polite.

How to be the patient who gets the right answer

Here is what I actually do now.

Track before you go, on paper. Two weeks of notes: the symptom, the date, how often, how much it interfered. Include your cycle. Specific beats vague every time. “I have been forgetful lately” invites a shrug. “I have misread a recipe measurement nine times in two weeks, and that used to happen twice a year” does not.

Lead with the change, not the symptom. Doctors hear “I am tired” all day. What is diagnostically interesting is the delta. Say what you used to be able to do and cannot do now.

Ask for the differential out loud. The single most useful question: “What else could cause this, and what would we do to rule those out?” It is a collaborative question, not a hostile one, and it changes the conversation from a verdict into a process.

Ask for the basic blood work by name. Thyroid function, ferritin and a complete blood count, vitamin B12, vitamin D, fasting glucose and A1C. These are inexpensive, ordinary tests that rule out several of the mimics in one draw.

Ask what happens if the first answer is wrong. “If we try this and I am not better in six weeks, what is the next step?” This builds a follow-up into the plan instead of leaving you to start over.

Ask for it in the chart. If you are told a symptom is not worth investigating, ask that the symptom and the decision both be documented. This is a reasonable request, and it tends to turn a casual dismissal into a considered judgment.

Bring someone, or bring notes. If brain fog is part of what you came in about, do not rely on your memory of the conversation. Write down what was said before you leave the parking lot.

Go somewhere else if you need to. If you leave an appointment feeling unheard, that is information. Getting a second opinion is not disloyalty. For menopause specifically, The Menopause Society certifies clinicians with demonstrated competence in this area and lists them, which is a faster route than trying your luck.

When to push instead of waiting

Most things resolve, and most symptoms are what they look like. But some patterns deserve to be escalated rather than monitored:

• A symptom that is constant rather than coming and going, especially over weeks
• A symptom that is getting steadily worse rather than staying level
• Bleeding that is new, unusually heavy, or happens after you thought you were finished with periods
• Any change in bowel habits that persists, or blood you cannot explain
• Unexplained weight loss
• Pain that wakes you from sleep
• Anything your gut is telling you is not normal for your body

That last one is not a clinical criterion, and I am including it anyway. You have lived inside your body your entire life. You know its baseline better than any person who has known you for fifteen minutes. When your instinct says something is wrong, that instinct is data, and it should be weighed rather than talked out of you.

What I want you to take from this

As we get older, we have to take the lead on our own health. Not because doctors are the enemy. Because a fifteen-minute appointment cannot possibly hold everything you know about your own body, and because nobody else is going to notice that a thing which used to happen twice a year is now happening twice a day.

Learn your own baseline. Notice when the rate changes. Write it down. Ask what else it could be. Ask what happens if the first answer is wrong. And if you do not like the answer you get, go find another doctor, without apologizing for it.

I was lucky twice. I was lucky that my brain fog turned out to be something treatable rather than something progressive. And I was lucky that I did not accept “it is just menstrual cramps,” because that stubbornness is the reason I was diagnosed at stage 2 rather than later.

I do not want you to have to be lucky. I want you to be informed, which works better.

Sources

• Pharmacological Management of ADHD in Women Across Perimenopause, Menopause and Post-Menopause, Wynchank D and Kooij JJS, Drugs & Aging, volume 43, pages 385 to 395, 2026.
• Perimenopausal symptoms in women with and without ADHD: A population-based cohort study, Jakobsdóttir Smári U, Valdimarsdottir UA, Wynchank D, et al., European Psychiatry, 2025.
• Menopause Symptoms Exacerbate ADHD in Women: ADDitude Survey, ADDitude magazine reader survey of more than 1,500 women.
• Survey of Young-onset Colorectal Cancer Patients Suggests Misdiagnosis May Be Common, American Association for Cancer Research.
• Menopause Symptoms, The Menopause Society.
• Most OB/GYN residency programs in US lack dedicated menopause curriculum, Healio Women’s Health and OB/GYN.