Anosognosia: The Brain-Based Condition That Hides Illness From Itself
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: September 2026
TL;DR
Anosognosia is a condition in which the brain cannot recognize one or more other health conditions a person has. Experts call it "denial of deficit" or "lack of insight." It is extremely common with mental health conditions like schizophrenia and Alzheimer's disease, affecting an estimated 50% to 98% of people with schizophrenia. The condition is not dangerous on its own, but it makes people far more likely to avoid or resist treatment for their other illnesses.
Quick Answer
What it is: Anosognosia is a brain-based condition in which a person cannot recognize that they have one or more other health conditions.
How common: Experts estimate it affects 50%–98% of people with schizophrenia, about 40% with bipolar disorder, more than 80% with Alzheimer's disease, and 10%–18% of people with one-sided paralysis after stroke.
Not the same as denial: Denial rejects reality because it is distressing, while anosognosia means the person cannot recognize the problem at all.
Treatment: There is no cure or direct medication; therapy helps build compensating habits, and treating the underlying brain injury may improve it over time.
What Is Anosognosia?
Anosognosia is a condition in which you cannot recognize other health conditions or problems that you have. Experts commonly describe it as "denial of deficit" or "lack of insight."
It falls under the family of agnosias — conditions that happen when the brain cannot recognize or process what the senses tell it. Anosognosia can happen with mental illnesses, keeping a person with a disorder like schizophrenia from recognizing that they have a condition and need to take medication. It can also happen with physical conditions, such as stroke.
While anosognosia is not dangerous on its own, people who have it are much more likely to avoid or resist treatment for their other health conditions.
How Common Is Anosognosia?
Anosognosia is incredibly common with certain mental health conditions. Experts estimate that it affects:
| Condition | Estimated prevalence of anosognosia | | --- | --- | | Schizophrenia | Between 50% and 98% | | Alzheimer's disease | More than 80% | | Bipolar disorder | About 40% | | One-sided paralysis after stroke | Between 10% and 18% |
It most commonly occurs alongside Alzheimer's disease, dementia, bipolar disorder, and schizophrenia. Anosognosia is not contagious.
How Does Anosognosia Affect the Body?
Your brain keeps track of what is going on with your body using a "self-image." If you have an injury, your body updates your self-image to reflect that, and it keeps updating as your body heals. People with anosognosia have damage in the areas of their brain that update their self-image.
Because their mind cannot update the self-image, they cannot process or recognize that they have a health problem. This is what makes the condition different from the denial described by the Kübler-Ross model (the five stages of grief):
| Comparison | Denial | Anosognosia | | --- | --- | --- | | What happens | The person rejects or avoids accepting reality because it is unpleasant or distressing | The person cannot recognize the problem at all | | Nature of the problem | Emotional response to difficult news | Brain-based inability to update the self-image | | Consciousness | A rejection of known reality | No recognition that a problem exists |
Because people with anosognosia cannot recognize they have a medical problem, they often do not see the need to care for that problem. In more severe cases, they actively avoid or resist treatment.
What Are the Symptoms of Anosognosia?
People with anosognosia usually show that they cannot recognize a medical problem they have, either through their actions or what they say. In some cases they rationalize what is happening to them, or they may try to cover up symptoms. They may recognize some symptoms but not others.
Specifically, anosognosia means a person cannot do one or more of the following:
| What the person cannot do | Description | | --- | --- | | Recognize the illness | Cannot recognize that they have an illness or medical problem | | Recognize symptoms | Cannot recognize the signs and symptoms they experience | | Connect symptoms to the condition | Cannot link their signs and symptoms to the condition | | Agree treatment is needed | Cannot understand and agree that the condition is serious and needs treatment |
Some people avoid the truth about their condition consciously or without realizing it. Some may confabulate — when the mind fills gaps in memory with false memories.
What Are the Recognizable Forms of Anosognosia?
Anosognosia appears in distinct forms, from one-sided body awareness loss to a rare visual syndrome.
One-Sided Sensory and Movement Problems
Anosognosia got its name from French neurologist Joseph Babinski in 1914, who created the term to describe someone who had lost the ability to use or feel the left side of their body yet was unaware of the problem. This one-sided form more commonly affects the left side of the body, but it can affect the right side.
Two key symptoms accompany this form:
| Symptom | What it means | | --- | --- | | Hemiplegia | Paralysis on one side of the body — a person with anosognosia who cannot move one side will still believe they can | | Hemisensory loss | Loss of senses — including vision, hearing, and touch — on one side of the body |
Anton's Syndrome (Visual Anosognosia)
Anton's syndrome is an extremely rare type of anosognosia that affects eyesight in one of two ways:
| Form | Description | | --- | --- | | Denial of blindness | A blind person cannot recognize that they are blind; usually affects both eyes, with rare exceptions such as "gun-barrel vision," where a person can see only in the center of their field of vision | | Denial of vision | A person says and believes they are blind but shows signs they can still see; much rarer than denial of blindness |
Mental Health Insight Loss
The most common everyday form affects people with mental health conditions. A person with schizophrenia, bipolar disorder, dementia, or Alzheimer's disease cannot recognize the illness itself — or the need to take their medication.
What Causes Anosognosia?
Anosognosia can happen for many different reasons, all of which fall into one of two categories: brain damage and degenerative diseases.
Brain Damage (Lesions)
Damage to the brain causes injuries called lesions, and lesions in the self-image updating areas can produce anosognosia:
| Cause of brain damage | Description | | --- | --- | | Aneurysms | A weakened, bulging blood vessel in the brain | | Brain tumors | Cancerous and non-cancerous growths | | Head injuries | Concussions and traumatic brain injuries (TBIs) | | Cerebral hypoxia | Brain damage from lack of oxygen | | Infections | Such as those that cause encephalitis | | Seizures and epilepsy | Abnormal electrical activity in the brain | | Sleep apnea | Repeated breathing interruptions during sleep | | Strokes | Interrupted blood flow to the brain | | Toxins | Such as carbon monoxide poisoning |
Degenerative Diseases
Many brain diseases disrupt the brain's network of connections. That disruption can affect the ability to update the self-image, leading to anosognosia:
| Degenerative disease | How it relates | | --- | --- | | Alzheimer's disease | More than 80% of people with Alzheimer's have anosognosia | | Bipolar disorder | About 40% of people with bipolar disorder have it | | Dementia | Commonly accompanies dementia conditions | | Huntington's disease | Disrupts the brain's network of connections | | Schizophrenia | 50%–98% of people with schizophrenia have it |
How Is Anosognosia Diagnosed?
Anosognosia is effectively invisible unless a provider already knows you have a health problem and sees signs that you do not recognize that problem. In many cases, the provider must first diagnose a condition that is significantly impacting your life, then see signs that you cannot recognize it.
Diagnosis is complicated because people with anosognosia often rationalize or cover up signs of health problems — their mind fills in the gaps for what it cannot explain or understand. Because of that, diagnosing the condition usually requires a combination of:
| Diagnostic step | Purpose | | --- | --- | | Physical and neurological exam | Identifies deficits the patient does not report | | Health history questions | Covers a person's health history and life circumstances | | Diagnostic testing and imaging | Confirms underlying brain damage or disease |
The imaging and diagnostic tests that may be used include a computerized tomography (CT) scan, an electroencephalogram (EEG), and magnetic resonance imaging (MRI).
How Is Anosognosia Treated?
Anosognosia is difficult to treat and is not curable. When it happens because of a brain injury, treating the underlying injury may help the condition over time — but some people have lingering or even permanent effects. When it happens because of degenerative diseases, it is not treatable, though some forms of therapy and treatment programs may help.
| What treatment cannot do | What treatment can do | | --- | --- | | There is no medication that directly helps anosognosia | Therapy and treatment programs help people develop compensating habits | | Anosognosia from degenerative diseases is not treatable | Treating the underlying brain injury may improve it over time | | It cannot be self-diagnosed or self-treated | These programs do not treat the condition itself |
It is important to note that anosognosia is not a condition to self-diagnose or self-treat. It often accompanies much more serious conditions that need care from a trained, experienced healthcare provider.
What Are the Possible Complications?
The possible complications depend entirely on the disorder the person has but cannot recognize. Because people with anosognosia cannot see they have a problem, they are less likely to accept and undergo treatment. For example, people with one-sided paralysis are much more at risk for fall injuries because they still think they can stand up.
A healthcare provider is the best person to explain possible complications, since they can tailor the information to the specific condition involved.
How Long Does Anosognosia Last?
The duration depends on the cause. When anosognosia comes from a lesion caused by brain injury, it is more likely to improve on its own — it may go away in some cases, but it can also be permanent. When it occurs with mental health conditions or degenerative brain disorders, anosognosia is permanent.
What Is the Outlook?
Anosognosia is not fatal or dangerous on its own, but it increases the risk of complications from other problems. People with the condition are also more likely to resist or avoid medical treatment for the condition they cannot recognize.
| Cause | Duration | Key risk | | --- | --- | --- | | Brain injury (lesion) | May improve on its own or be permanent | Complications from the unrecognized injury | | Mental health or degenerative disease | Permanent | Resisting or avoiding treatment; missed medications |
Can Anosognosia Be Prevented?
Anosognosia happens unpredictably and is not preventable. It must occur alongside another condition, such as stroke or schizophrenia — but having those conditions is not a guarantee of developing anosognosia.
It is still a good idea to protect your brain, which reduces the risk of the conditions that can lead to anosognosia:
| Brain-protection habit | Why it matters | | --- | --- | | Eat a balanced diet and maintain a healthy weight | Many circulatory and heart conditions, especially stroke, can cause brain damage | | Don't ignore infections | Eye and ear infections that spread to the brain can become serious or deadly | | Wear safety equipment | Helmets are essential at work and during off-hours to prevent head injuries | | Manage your health conditions | Managing conditions — especially schizophrenia — helps avoid situations where an unmanaged condition becomes much worse |
How Should People With Anosognosia Take Care of Themselves?
Following your healthcare provider's guidance is essential, because your inability to see your health conditions makes you dependent on their expertise. That includes keeping appointments as recommended, taking medications as prescribed, and watching for any symptom changes you cannot explain.
How Should Families Respond?
Anosognosia can be confusing and frightening. To others, it might seem like stubbornness or living in denial — when in reality, the condition affects a person's ability to understand what is happening to their own body.
Building a trusting relationship with the healthcare provider and relying on their expertise is critical. For people who have the condition, patience and understanding matter: a strong support system and the help of loved ones can make a big difference, minimizing the effects on the connected condition and on everyone's health and well-being.
Conclusion
Anosognosia is one of the most misunderstood conditions in medicine. To families and friends, a loved one who refuses to acknowledge their schizophrenia or their paralysis can look stubborn or "in denial." In reality, the person's brain cannot update its own self-image — the recognition itself is missing, not the courage to accept it.
The condition is remarkably common: most people with schizophrenia and most people with Alzheimer's disease experience it. It cannot be cured, and no medication treats it directly, but the underlying injury can improve with time, and therapy helps people build habits that compensate for lost insight.
CTA: If a loved one with schizophrenia, bipolar disorder, dementia, or Alzheimer's disease consistently refuses to acknowledge symptoms or avoid medication — or if someone with one-sided paralysis insists they can still move normally — talk to their healthcare provider. Trust their guidance, keep follow-up appointments, and lean on a strong support system; patience and understanding from loved ones make a real difference.
FAQ
What is anosognosia?
Anosognosia is a brain-based condition in which a person cannot recognize one or more other health conditions they have. Experts describe it as "denial of deficit" or "lack of insight."
How common is anosognosia?
Experts estimate it affects between 50% and 98% of people with schizophrenia, about 40% of people with bipolar disorder, more than 80% of people with Alzheimer's disease, and 10% to 18% of people who have one-sided paralysis after a stroke.
Is anosognosia the same as denial?
No. Denial means a person rejects or avoids accepting reality because it is unpleasant or distressing. Anosognosia means the person cannot recognize the problem at all, because the brain areas that update their "self-image" are damaged.
What causes anosognosia?
Causes fall into two categories: brain damage (lesions from aneurysms, brain tumors, head injuries, strokes, cerebral hypoxia, infections, seizures, sleep apnea, or toxins) and degenerative diseases (Alzheimer's disease, dementia, bipolar disorder, Huntington's disease, schizophrenia).
What are the symptoms?
A person cannot recognize that they have an illness, cannot recognize their own signs and symptoms, cannot connect symptoms to the condition, or cannot agree the condition is serious and needs treatment. They may rationalize or cover up symptoms, or confabulate — filling memory gaps with false memories.
What is Anton's syndrome?
Anton's syndrome is an extremely rare form of visual anosognosia. In the more common form, a blind person cannot recognize that they are blind; in the rarer form, a person believes they are blind but shows signs they can still see.
How is it diagnosed?
Providers combine a physical and neurological exam, questions about health history and life circumstances, and diagnostic imaging such as CT scan, MRI, or EEG, since the condition is effectively invisible unless the provider already knows of the underlying problem.
Is anosognosia curable?
No. It is not curable and no medication treats it directly. Therapy can help a person develop compensating habits, and treating the underlying brain injury may help it improve over time — but anosognosia from degenerative diseases is permanent.
References
Acharya AB, Sánchez-Manso JC. Anosognosia. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022. Updated 2021 Aug 1. https://www.ncbi.nlm.nih.gov/books/NBK513361/
Chaudhry FB, Raza S, Ahmad U. Anton's syndrome: a rare and unusual form of blindness. BMJ Case Rep. 2019;12(12):e228103. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7001702/
Lehrer DS, Lorenz J. Anosognosia in schizophrenia: hidden in plain sight. Innov Clin Neurosci. 2014;11(5-6):10-17. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4140620/
Smith AJ, Campbell RW, Harrison PK, Harrison DW. Functional cerebral space theory: Towards an integration of theory and mechanisms of left hemineglect, anosognosia, and anosodiaphoria. NeuroRehabilitation. 2016;38(2):147-154. https://pubmed.ncbi.nlm.nih.gov/26889731/
Baula TL. Awareness of the Unaware: Anosognosia as a Comorbidity in Mental Health Conditions. University of Central Florida Honors Undergraduate Theses. https://stars.library.ucf.edu/cgi/viewcontent.cgi?article=1820&context=honorstheses
Medical Disclaimer: This article is for general informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified healthcare provider with any questions you may have about a medical condition. Anosognosia should never be self-diagnosed or self-treated — consult a trained healthcare professional, and seek immediate care for sudden neurological symptoms such as weakness on one side of the body.
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