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For the person with the diagnosis · Your decisions

When the Diagnosis Does Not Feel Right

Maybe it came too fast, or too slow, or it does not match what you are living. Asking for a second look is reasonable, and sometimes it changes things.

Key takeaways

  • Asking for a second opinion is normal, and good doctors expect it. You are not being difficult. The type of dementia changes treatment, safety and planning.
  • Clinical diagnosis without biomarkers has been wrong a meaningful share of the time. In a 2012 study of 526 people diagnosed with probable Alzheimer's at specialist centers, about 17% had too little Alzheimer's pathology at autopsy to explain it.
  • Biomarker tests have changed this. An amyloid PET scan, spinal fluid test or validated blood test can now confirm or rule out Alzheimer's pathology in a living person.
  • Younger people wait longer for answers. In one study, diagnosis took about 4.4 years from first symptoms for people under 65, compared with 2.8 years for older people, and frontotemporal dementia took longest.
  • Be realistic about "reversible dementia." About 9% of cases had a potentially reversible cause in a large review, but only about 0.6% actually reversed. The workup is still worth doing.

Is it OK to ask for a second opinion?

Yes. It is an ordinary request, and with a diagnosis this consequential, many specialists expect it.

People hesitate because they do not want to seem ungrateful or to insult a doctor they will keep seeing. But a dementia diagnosis decides a lot: which medicines are safe, whether you qualify for newer treatments, how you plan for work and money, and what your family prepares for. Getting it right is worth a second look.

Some people have the opposite problem. One person in a caregiver group wrote that they had to threaten to change doctors before anyone would give them a diagnosis at all. If you have been told for years that it is "just stress" or "normal aging" and you know it is not, that is also a reason to see someone else.

How often is a dementia diagnosis wrong?

Less often than it used to be, now that biomarker tests exist. Without them, the error rate at even the best centers was not small.

The clearest evidence comes from comparing diagnosis in life with what is found at autopsy. A 2012 study in the Journal of Neuropathology and Experimental Neurology looked at 919 people seen at NIA-funded Alzheimer's centers between 2005 and 2010. Of 526 people diagnosed with probable Alzheimer's disease, about 17% had too little Alzheimer's pathology to account for their symptoms. Many of them had other conditions instead: frontotemporal degeneration, vascular disease or Lewy body disease. Depending on the definitions used, the clinical diagnosis caught 71% to 87% of true Alzheimer's cases.

Those were specialist centers, and the study predates routine biomarker testing. Today, an amyloid PET scan, a spinal fluid test, or a blood test that meets the Alzheimer's Association's accuracy standards can confirm or rule out Alzheimer's pathology while you are alive. If your diagnosis was made on symptoms and memory testing alone, asking whether a biomarker test would help is a reasonable question.

When does a second opinion make the most sense?

When the type of dementia is uncertain, when the symptoms do not fit, when you are younger, or when nobody has looked for other causes.

Could something else be causing my symptoms?

Sometimes, and the checks are routine. Be realistic about the odds, though: true reversal is uncommon.

Conditions that can cause or worsen memory and thinking problems include vitamin B12 deficiency, thyroid disease, depression, sleep apnea, medication side effects, hearing loss, heavy alcohol use and normal pressure hydrocephalus.

A 2003 meta-analysis in the Archives of Internal Medicine found that about 9% of people being evaluated for dementia had a potentially reversible cause, but only about 0.6% actually got better with treatment. That gap matters. It means the workup is worth doing, and it also means a second opinion is more likely to sharpen your diagnosis than to make it disappear. Even when the dementia remains, treating a contributing problem such as depression, sleep apnea or a medication side effect can make daily life noticeably better.

Who should I see for a second opinion?

Ideally a specialist who focuses on memory and thinking disorders, at a center that can do biomarker testing.

Check with your insurance about referrals and coverage before you book, and ask whether your plan needs a referral from your doctor.

What should I bring?

Your records, your questions, and someone who knows you well. The second doctor should not have to start from nothing.

If the second opinion agrees with the first, that has value too. Some people find that hearing the same answer twice, from two careful doctors, is what finally let them stop questioning it and start planning.

Frequently asked questions

Can I get a second opinion on a dementia diagnosis?
Yes. It is a common and reasonable request, especially when the type of dementia is unclear, symptoms do not fit, or you are under 65. A behavioral neurologist or memory specialist at an academic center or Alzheimer's Disease Research Center is a good choice.
How often is Alzheimer's misdiagnosed?
Without biomarker tests, more often than people expect. In a 2012 study of patients seen at NIA-funded Alzheimer's centers, about 17% of people diagnosed with probable Alzheimer's had too little Alzheimer's pathology at autopsy to explain their symptoms. Biomarker tests now available can confirm the diagnosis in life.
Why does it take so long to diagnose young-onset dementia?
Symptoms are often mistaken for stress, depression or other midlife problems. A 2013 study found young-onset dementia took about 4.4 years from first symptoms to diagnosis, compared with 2.8 years for later onset, with frontotemporal dementia taking longest.
Can dementia be reversed if it is caused by something else?
Rarely. A 2003 meta-analysis found about 9% of people evaluated had a potentially reversible cause, but only about 0.6% actually got better with treatment. Treating contributors such as depression, sleep apnea, B12 deficiency or medication side effects can still improve how you feel and function.
What tests confirm Alzheimer's disease?
An amyloid PET scan, a spinal fluid test, or a validated blood test such as one measuring p-tau217 can show whether Alzheimer's pathology is present. They are usually used together with your symptoms and memory testing rather than on their own.
What should I bring to a second opinion appointment?
Bring copies of your brain scans, the full memory testing report, blood work, a medication list, a short timeline of changes, your written questions, and someone who knows you well.

A room where the writing is addressed to you.

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Sources

  1. Beach TG, Monsell SE, Phillips LE, Kukull W, "Accuracy of the clinical diagnosis of Alzheimer disease at National Institute on Aging Alzheimer Disease Centers, 2005–2010," *Journal of Neuropathology and Experimental Neurology*, 2012.
  2. van Vliet D, de Vugt ME, Bakker C, et al., "Time to diagnosis in young-onset dementia as compared with late-onset dementia," *Psychological Medicine*, 2013.
  3. Clarfield AM, "The decreasing prevalence of reversible dementias: an updated meta-analysis," *Archives of Internal Medicine*, 2003.
  4. Alzheimer's Association, "Clinical practice guideline for blood-based biomarkers in the diagnostic workup of Alzheimer's disease within specialized care settings," *Alzheimer's & Dementia*, 2025.
  5. McKeith I, Fairbairn A, Perry R, Thompson P, Perry E, "Neuroleptic sensitivity in patients with senile dementia of Lewy body type," *BMJ*, 1992.
Peer support and education, not medical care. Only clinicians who have examined you and reviewed your tests can confirm or change a diagnosis. Check your insurance coverage before booking a second opinion.