According to Johns Hopkins Medicine data, an estimated 12 million American adults are medically misdiagnosed every year. In mild cases, such mistakes waste patient time; in other cases, someone’s symptoms worsen; in extreme cases, people lose their lives.
This Schiller Kessler Group study will closely consider America’s most commonly misdiagnosed conditions. And it’s a significant issue that’s rooted in overburdened healthcare systems, symptom overlap between conditions, and biases that can mean some patients are misread or even dismissed by medical professionals.
We’ll look at the scale of the problem, the mental health toll, the conditions most often misdiagnosed, and the dangers of being prescribed the wrong medicine. We’ll also consider who is most affected, and the cost of medical errors.
Before we look at the most commonly misdiagnosed conditions, let’s consider some broad factors regarding a national misdiagnosis problem.
America’s Misdiagnosis Problem
The fact that nearly 3.5% of the U.S. population is misdiagnosed every year reflects a systemic failure as opposed to a series of unfortunate mistakes.
Patients may be subject to delayed or incorrect treatments, undergo the wrong procedures, or take medications that involve dangerous side effects: all while their actual condition goes untreated. Some spend years moving from one medical professional to the next before belatedly receiving the correct diagnosis.
In extreme cases, diagnostic errors can lead to permanent disability or death. Every year, around 795,000 Americans suffer such serious harm: 424,000 are permanently disabled, while 371,000 die.
There’s also significant psychological damage, with patients frequently suggesting they feel dismissed, gaslit, or told their symptoms are imaginary.
This is especially evident regarding conditions like lupus and endometriosis, with many patients initially told there’s nothing medically wrong before they’re eventually taken seriously. This kind of failure delays treatment and erodes trust in medical professionals. It can also leave lasting psychological scars long after the right diagnosis has been found.
It’s a serious enough issue that “medical gaslighting” (clinicians dismissing concerns raised by patients, families, or caregivers) was ranked the number 1 patient safety concern in ECRI’s 2025 Top 10 Patient Safety Concerns report. ECRI directly links it to misdiagnosis, delayed treatment, and lasting emotional trauma.
Additionally, a HealthCentral reader survey tells us that more than 94% of respondents said a doctor ignored or dismissed their worries; 61% said they were blamed or made to feel delusional; 55% said their condition subsequently deteriorated as a result. 28% also reported that the delay in correct treatment eventually led to a health emergency.
The psychological effects are especially severe for patients who were eventually diagnosed with autoimmune disease. More than 80% said an initial misdiagnosis damaged their self-worth, with 72% saying the experience continues to upset them, years later.
ECRI researchers make it clear: such experiences can cause patients to lose trust in both medical professionals and in the wider healthcare system. This then makes them less likely to seek care when they need it, which can potentially turn a single diagnostic error into a lasting barrier to getting better.
But which conditions are the most commonly misdiagnosed?
The Most Commonly Misdiagnosed Conditions
Many conditions are regularly misdiagnosed, but different types of misdiagnosis involve a variety of consequences. Outcomes may also vary depending on a patient’s gender or race (a 2024 Johns Hopkins analysis found that women and racial or ethnic minorities are up to 30% more likely than White men to be misdiagnosed).
The conditions doctors most often misdiagnose can be categorized into three discrete groups: acute, time-sensitive illnesses; chronic autoimmune and inflammatory conditions; and mental and neurological conditions.
Acute Conditions
When it comes to the misdiagnosis of acute conditions, heart attacks are the leading problem. This affects an estimated 805,000 Americans every year: around 605,000 initial attacks and 200,000 recurrent ones.
Women have an up to 59% higher chance of heart attack misdiagnosis than men, partly due to the fact that they’re more likely to experience shortness of breath, nausea, back or jaw pain, and unexpected fatigue as opposed to the more obvious crushing chest pain. Many of the aforementioned symptoms are often misattributed to anxiety or panic attacks, wasting potentially critical time.
Stroke affects around 795,000 Americans every year (one person every 40 seconds), and is misdiagnosed in around 17% of cases. Sudden numbness or weakness, confusion, slurred speech, loss of sight, and severe headaches are often mistaken for migraines or vertigo. If a stroke is missed, it can ultimately lead to permanent brain damage.
Stroke is also subject to clear and worrying racial disparities. A 2024 analysis of over 34,500 cases found early stroke identification was missed more often among Black patients (34.9% of cases) than White patients (31.4% of cases).
Hispanic patients also suffer: just 18% of Spanish-speaking Hispanic populations could identify all five major stroke warning signs, compared with 50% of non-Hispanic White patients. Data also suggests that Hispanic patients waited an average of 21.3 minutes longer for a physician to decide on treatment.
In 2026, lung cancer is projected to be diagnosed in 226,650 U.S. patients. Its early symptoms (persistent cough, chest pain, shortness of breath, and sudden weight loss) are mistaken for pneumonia or bronchitis in 25% of cases, with often severe results, as early treatment is often vital.
And for those suffering from lung cancer, the five-year survival rate is roughly 60%-65% when the condition is caught early; the survival rate falls to just 12% at stage four.
2025 American Cancer Society data tells us that just 24% of Black patients were diagnosed early, compared with 28% of White patients.
Chronic and Autoimmune Conditions
Chronic and autoimmune conditions are usually subject to a far broader timescale than acute conditions. Some patients spend a decade or more suffering issues due to the wrong diagnosis.
Endometriosis affects approximately 1 in 10 women of reproductive age. It’s misdiagnosed in 75% of cases, usually as IBS, ovarian cysts, or appendicitis, due to overlapping symptoms such as pelvic pain, painful periods, and digestive problems. Diagnostic delays before endometriosis is established can last years.
Endometriosis is especially underdiagnosed among Black women, who are 50% less likely than White women to be correctly diagnosed.
Lupus affects about 1.5 million Americans and is misdiagnosed in 46.5% of cases, often as fibromyalgia or rheumatoid arthritis. Although all three conditions share joint pain, fatigue, and skin problems, untreated lupus can cause permanent kidney, heart, or lung damage. The average time a patient waits for a correct lupus diagnosis is six years.
Lupus also underscores a demographic disparity. Black women are affected at roughly three times the rate of White women; for Black women, the condition presents about six years earlier, and more often progresses to severe complications like kidney failure.
A misdiagnosis therefore hits even harder for patients who already face a more aggressive form of the disease. For Asian-American patients, lupus severity scores average 7.1 (compared to 6.5 for White patients), while diagnosis occurs at a younger age (27.9 years, compared to 29.4 years for White patients).
Fibromyalgia affects around 10 million Americans and is subject to a 50% misdiagnosis rate. It’s often confused with lupus or rheumatoid arthritis due to shared symptoms like pain, fatigue, trouble sleeping, and cognitive issues. And far more women than men suffer from fibromyalgia: 4.2% (compared to 1.4% of men).
Celiac disease, which affects about 1 in 133 Americans, is misdiagnosed in around 25% of cases. It’s often mistaken for IBS as both conditions cause bloating, cramping, and digestive issues. Untreated, celiac disease can cause intestinal damage and nutrient deficiencies and necessitates a strict dietary routine.
Lyme disease, which is diagnosed around 475,000 times every year, is subject to a 30%-50% misdiagnosis rate. Known as the “great imitator,” it can suggest MS, fibromyalgia, and lupus. Early, key signs of rash, fever, and fatigue often go unnoticed, while later joint and neurological issues are often wrongly attributed to other chronic conditions.
Mental and Neurological Conditions
Misdiagnosed mental and neurological conditions represent a different kind of danger. A wrong diagnosis can lead to new risks as opposed to simply delaying treatment.
Bipolar disorder affects around 5.7 million American adults and has the second highest misdiagnosis rate in this dataset (69%).
Most cases of misdiagnosis involve the disorder being mistaken for major depression. The distinction is especially important due to the fact that antidepressants can trigger manic episodes. Over a third of patients spend 10 years or more suffering the consequences of the wrong diagnosis.
And for those suffering from bipolar disorder, suicide rates are 10-30 times higher than they are for the general population, an aggravating factor that may well be worse among patients left untreated after a depression misdiagnosis.
Black patients are up to 4 times more likely to be misdiagnosed with schizophrenia, with clinicians often overemphasizing psychotic symptoms and failing to recognize key mood symptoms.
For Asian-American patients, mood disorders are often completely missed: in 2024, they were 45% less likely than the general population to receive mental health treatment, an issue linked to cultural stigma, the “model minority” myth, and a greater exhibition of psychological distress through physical issues.
Multiple sclerosis, which affects about 1 million Americans, is misdiagnosed in around 18% of cases, usually as migraine. Although both can cause headaches and neurological problems, untreated MS can result in progressive brain and spinal-cord damage that can lead to a permanent disability.
Multiple sclerosis is also subject to key racial and gender disparities. The condition affects women at nearly three times the rate it affects men, suggesting the possibility that women’s symptoms receive differing levels of investigation compared to men.
Additionally, when a diagnosis of MS is first carried out, 38.3% of Black patients already present vision loss (compared with 28.6% of White patients), while 70% need to be hospitalized early.
The overall pattern is consistent across all three categories: overlapping symptoms, rushed appointments, and a tendency to offer the most common or convenient explanation for a medical problem without fully considering alternatives. And patients often suffer as a result, over varying periods of time and with a variety of health consequences (which can widely differ depending on a patient’s gender and race).
And the consequences for being given the wrong medication can be severe.
Wrong Prescriptions, Following Misdiagnosis
Far from being just a matter of lost time, a missed diagnosis can represent serious immediate danger. That’s the case when a patient is wrongly prescribed a powerful medication, or too much of the right one.
AHRQ estimates that adverse reactions to drugs lead to around 700,000 emergency visits and 100,000 hospital admissions every year. Worse still, a 2025 American Society of Pharmacovigilance study suggested that drug-related harm may kill up to 300,000 Americans a year. Yet over 94% of adverse drug reactions are unreported, meaning regulators are missing key data. Three out of four medication errors are due to an incorrect dosage as opposed to a patient being prescribed the wrong drug.
Depending on the medication in question, the consequences vary. Nearly a third of outpatient antibiotic prescriptions (around 47 million a year) treat infections that aren’t bacterial, in many cases because viral cold and cough symptoms are wrongly labeled bacterial.
Antibiotics can trigger C. difficile, a severe intestinal infection that causes up to 250,000 hospitalizations and 14,000 deaths every year. Additionally, antibiotic-resistant infections lead to over 2.8 million infections and around 35,000 deaths each year.
Opioids are also very risky when prescribed for pain if the underlying cause isn’t identified. Nearly 1 in 10 patients who take opioids for chronic pain develop dependence or opioid use disorder; 8.6 million Americans said they misused prescription opioids.
The cumulative effect of corticosteroids can be serious. Around 9 in 10 patients who take them for over two months develop adverse reactions such as adrenal suppression, bone loss, diabetes, and cardiovascular complications.
For up to 70% of bipolar patients who are mistakenly diagnosed as suffering from ordinary depression, the use of antidepressants can trigger mania and rapid condition fluctuation.
Ultimately, in such cases, C. difficile, opioid dependence, steroid-related psychiatric symptoms, and medication-induced mania are not drug failures: they’re the consequence of an incorrect diagnosis.
And there are also significant financial consequences to consider regarding patient misdiagnosis.
The Costs of Misdiagnosis
Diagnostic errors (including subsequent treatments and corrective care) represent 17.5% of total U.S. healthcare spending: that’s an estimated $870 billion a year.
For patients, that cost affects ordinary medical bills. Repeat imaging after a wrong diagnosis can cost up to $2,000 for an MRI at an independent center or up to $8,000 at a hospital. A CT may cost around $525 as an outpatient; that rises to about $4,750 as an inpatient.
If we factor in a specialist visit (typically a $20-$75 copay) and the average $1,886 health insurance deductible (2025 figures), patients can quickly end up paying significant sums.
Patients also often lose significant amounts of time to misdiagnosis.
Fibromyalgia patients see an average of 3.7 physicians and wait 2.3 years for the right diagnosis. For lupus patients, the wait is often much longer: up to 63% report an earlier misdiagnosis, 68% see at least three doctors, 11% see 10 or more, and the average diagnostic delay runs to over six years.
Endometriosis patients suffer the longest average wait on this list (11 years); more than a third of bipolar disorder patients spend over 10 years without the right diagnosis.
For multiple sclerosis patients, things are improving in this regard: diagnostic delays have fallen from 4.2 years in the early 2000s to 1.1 years in 2025. That said, 40.4% of patients say they’re still initially misdiagnosed, with more than 1 in 5 waiting over a year for the right diagnosis.
While patients suffering from acute conditions rarely spend years waiting for the right diagnosis, delays can still be significant. Lung cancer takes an average of 122 days from first symptoms to definitive diagnosis, including 65 days spent requesting, performing, and checking scans. If another condition provides a feasible alternative explanation, the delay can increase by a further 72 days.
For stroke victims, 9% go unrecognized during the first appointment assessment. Among patients later hospitalized for stroke, up to 12.7% had already been sent home from an ER after a misdiagnosis such as an inner-ear infection or migraine.
Women under 55 presenting heart attack symptoms are seven times more likely than men to be sent home from the ER without proper cardiac testing.
Premature closure (settling on the first plausible explanation instead of ruling out alternatives) contributes to an estimated 47% of diagnostic errors.
The Varied Costs of Medical Misdiagnosis in America
Diagnostic failures represent a widespread systemic problem that affects millions of Americans. They cause delayed or incorrect treatment, medication-related harm, psychological distress, permanent disability, and death, and disproportionately affect women and racial and ethnic minorities. Beyond the human costs, the financial consequences are significant, with an estimated $870 billion lost every year in the U.S.
The recurring pattern is clear: clinicians too often settle on the first plausible explanation instead of continuing to investigate until the correct diagnosis is confirmed. Until this trend is significantly mitigated, the losses emphasized by this study will continue.
The Schiller Kessler Group Supports Patients Who Have Been Misdiagnosed
You should be able to reasonably expect a standard of care from a licensed medical professional. When that standard of care hasn’t been met, you may be left with unnecessary (and often avoidable) pain and suffering.
If you have suffered an injury due to medical negligence, you may be entitled to financial compensation. At the Schiller Kessler Group, our experienced and passionate Florida medical malpractice lawyers can help protect your rights and will work hard to get you the compensation you deserve.
