Alzheimer’s disease is harder to diagnose accurately than many families assume. In a 2017 study of 961 people whose diagnoses could be checked against brain autopsy findings, researchers found that the clinical diagnosis of Alzheimer’s was wrong in about 24 percent of cases, with false positives and false negatives each making up about 12 percent.
This post first ran in July 2017, shortly after that study was published. Here, the Houston medical malpractice attorneys at Davis & Davis explain what the research found, why psychotic symptoms can cloud the picture, which treatable conditions can look like Alzheimer’s, and when a wrong or missed diagnosis may become a failure to diagnose claim under Texas law.
What the 2017 Study Found
The study, by researchers at St. Michael’s Hospital in Toronto, was published in the journal Alzheimer’s & Dementia: Translational Research & Clinical Interventions. It drew on the National Alzheimer’s Coordinating Center database, which collects information from 29 Alzheimer’s disease centers in the United States. The researchers looked at 961 people seen between 2005 and 2012 and compared the diagnosis each person received during life with what an autopsy later showed in the brain.
About 76 percent of the diagnoses were correct. About 12 percent were false positives, meaning the person was diagnosed with Alzheimer’s but the autopsy did not show the disease, and about 12 percent were false negatives, meaning Alzheimer’s was present but had not been diagnosed. The authors pointed out that most people in the database had been examined by clinicians who concentrate on dementia, and that the diagnosis studied was the last one made before death. For those reasons, they described their error rates as a minimum reached under favorable conditions. In ordinary practice, the rate may be higher.
Why Psychotic Symptoms Can Lead to a Wrong Diagnosis
The study’s main focus was psychosis, meaning delusions or hallucinations, which some people with Alzheimer’s develop. Patients with psychosis had a higher rate of false-negative diagnoses than patients without it. In other words, when psychotic symptoms were present, Alzheimer’s was more likely to be missed and the symptoms attributed to something else, such as another type of dementia or a psychiatric illness. Whether a patient had delusions, hallucinations, or both did not change the result.
The original version of this post said that these symptoms may lead doctors to believe a patient has dementia instead of Alzheimer’s. That framing was not quite right. Dementia is a general term for a decline in memory and thinking, and Alzheimer’s disease is its most common cause. The real diagnostic challenge is telling Alzheimer’s apart from the other conditions that can cause similar symptoms.
Treatable Conditions That Can Look Like Alzheimer’s
According to the National Institute on Aging, the workup for memory problems includes blood, urine, and other standard tests, a review of prescription and over-the-counter medicines, and a psychiatric evaluation, partly to find other possible causes of the symptoms. Some of those causes may be treatable and possibly reversible. Conditions that a careful evaluation should consider include:
- Medication side effects: Some commonly prescribed drugs, alone or in combination, can cause confusion or memory problems, especially in older adults.
- Depression and other mental health conditions: These can affect concentration and memory and can be mistaken for cognitive decline.
- Hormone and vitamin problems: Abnormal levels of certain hormones and vitamins, such as thyroid problems or a vitamin B12 deficiency, can affect thinking and memory.
- Thiamine (vitamin B1) deficiency: A severe deficiency can cause Wernicke’s encephalopathy and, if it progresses, Korsakoff syndrome, which involves serious memory loss.
Our firm has written extensively about missed thiamine deficiency. Our page on thiamine deficiency misdiagnosis and our article on how doctors misdiagnose Wernicke’s encephalopathy explain why this condition is sometimes mistaken for dementia or other illnesses.
Why an Accurate Diagnosis Matters
A wrong diagnosis can cause harm in either direction. When a treatable condition is labeled as Alzheimer’s, the real cause may go untreated while the person continues to decline. When Alzheimer’s is missed, the person and the family may lose time to plan for care, address safety concerns such as driving and medication management, and consider treatment options. Since 2023, the U.S. Food and Drug Administration has approved medicines for early Alzheimer’s that are intended for patients with confirmed amyloid in the brain, which makes an accurate and timely diagnosis more important than it was when this post first ran.
An accurate diagnosis also matters for families making legal and financial decisions, such as powers of attorney or guardianship, and for anyone trying to understand whether a decline in a relative’s condition was preventable.
When a Dementia Diagnosis Error May Be Malpractice
Not every wrong diagnosis is malpractice. As the 2017 study shows, Alzheimer’s disease can be misdiagnosed even at dedicated research centers. The legal question is whether the provider did what a reasonably careful provider in the same field would have done under the same circumstances, and whether a failure to do so caused harm. Examples that may deserve a closer look include not checking for treatable causes of memory loss, overlooking a medication that could explain new confusion, failing to follow up on abnormal lab results, or not referring a patient for further evaluation when the picture did not fit.
In Texas, these cases are health care liability claims under Chapter 74 of the Civil Practice and Remedies Code. Under section 74.251, a claim generally must be filed within two years from the date of the breach or from the date the related course of treatment or hospitalization ended. Texas does not apply a general discovery rule to these claims, and the statute states that the deadline applies to people with legal disabilities, apart from narrow exceptions. That matters when the patient has dementia and a family member or legal representative has to act on their behalf. The claimant must also give written notice at least 60 days before filing suit, which tolls the deadline for 75 days, and must serve a report from a qualified medical professional within 120 days after each defendant files an answer.
Talk With Davis & Davis About a Missed or Wrong Diagnosis
Our firm focuses on medical malpractice, including diagnosis errors involving memory loss, confusion, and neurological conditions. We review medical records, medication lists, and test results with qualified medical professionals to determine whether the care met accepted standards. Every case is different, and we cannot promise a particular result.
If you believe a doctor missed or misidentified the cause of a family member’s cognitive decline, contact Davis & Davis to request a free consultation and learn more about your options.
Source: NewsMedical.net, “Study highlights rate of misdiagnosis in Alzheimer’s disease patients with psychosis,” June 30, 2017
Frequently Asked Questions About Alzheimer’s Misdiagnosis
How often is Alzheimer’s disease misdiagnosed?
In a 2017 study comparing clinical diagnoses with autopsy findings in 961 people, the diagnosis was wrong in about 24 percent of cases, split evenly between false positives and false negatives. Because the patients were mostly seen at dedicated dementia research centers, the authors considered that rate a minimum.
Is Alzheimer’s disease the same thing as dementia?
No. Dementia is a general term for a decline in memory, thinking, and reasoning that interferes with daily life. Alzheimer’s disease is the most common cause of dementia, but other conditions, including other brain diseases and some treatable medical problems, can cause similar symptoms.
What conditions can be mistaken for Alzheimer’s?
Medication side effects, depression, thyroid problems, and vitamin deficiencies such as low vitamin B12 or thiamine can all affect memory and thinking. A careful evaluation uses blood tests, a medication review, and other assessments to look for these causes, some of which may be treatable.
Can we sue if a doctor missed a treatable cause of memory loss?
Possibly. A claim may exist if the provider failed to do what a reasonably careful provider would have done, such as checking for common treatable causes, and that failure caused harm that timely treatment could have prevented. A review of the medical records by a qualified medical professional is usually the first step.
Does dementia extend the deadline to file a malpractice claim in Texas?
Generally, no. Texas Civil Practice and Remedies Code section 74.251 sets a two-year deadline that runs from the date of the breach or the end of the related treatment, and it states that the limit applies to people with legal disabilities, apart from narrow exceptions. Families should speak with an attorney promptly rather than wait.
