Health and Disease

Anosognosia – Not Knowing What You Don’t Know

By Melle Hsing

Published 3:12 PM EST, Sat April 3, 2021


Patients may respond differently to news about their health — with sadness, shock, anger, relief, and more. In some cases, patients do not know how to respond, not because of denial but the lack of self-awareness in noticing  a problem. This condition is called anosognosia, which refers to the failure of an individual to recognise that they have a disorder or mental illness. Someone not knowing that they have anosognosia is in and of itself anosognosia. They may say phrases such as “there’s nothing wrong with me!” or “I don’t need your help”. With a lack of insight, a patient may refuse to get a proper medical check-up or receive crucial treatment for their illness. This article raises awareness of anosognosia as a real mental condition and  the causes and consequences of it. Undoubtedly, anosognosia also highlights the importance of a doctor’s insight.

Causes and Consequences

How does anosognosia differ from when the patient doesn’t know about the existence of their disease simply because the symptoms are hard to observe in real life? Well, patients with this condition may still believe that nothing is wrong with them even when there is strong evidence of a diagnosis, stemming from the  structural changes in their brain. The presentation of a medical condition differs from person to person, and hence the symptoms of anosognosia can manifest in various ways depending on the individual. Some may feel anger when others tell them that something they disagree with, while others may shrug off opinions. There are also those who acknowledge that they have a disease or illness one day, and refuse to believe they have it in the next. Being able to differentiate between ignorance and real disbelief is one of the challenging parts of diagnosing anosognosia.

Not all researchers agree with each other when talking about the influence of demographics on the occurrence of anosognosia. Since patients lack awareness of their illness, this means that anosognosia can only be present by definition in those with health problems, in particular, mental illnesses. Is there a biological link between a particular mental illness and anosognosia? 

According to the National Alliance on Mental Illness, 60% of schizophrenic patients do not believe that they have schizophrenia. There have also been cases where patients with bipolar disorder, Huntington’s, Alzheimer’s, Parkinson’s, and traumatic brain injury lack insight to their health issues. Studies involving patients with schizophrenia have given researchers insight to the possible biological causes of anosognosia in the brain. Self-awareness is localised in many parts of the brain in a broad network, particularly anatomical structures in the frontal lobes and parietal lobes, hence anosognosia may arise from deficient activation in these areas.

Serious Mental Illness and Anosognosia - Treatment Advocacy Center

Figure 1: Differences in brain activation between patients with low insight and high insight. Sourced from the Treatment Advocacy Center (Brain scans).

Anosognosia is the main reason why patients with schizophrenia and bipolar disorder refuse treatment. Hence, support from family members, friends, and healthcare professionals is very important to the benefit of the patient’s health.

The Doctor’s Insight

As Oliver Sacks once said, “it is singularly difficult, for even the most sensitive observer, to picture the inner state, the ‘situation’ of such patients, for this is almost unimaginably remote from anything he himself has ever known.” Empathy plays an integral role in doctor-patient communication because patients with anosognosia may feel genuinely confused, misunderstood, and even discriminated against due to the conflicting views about their own health. Hence, doctors need to think about how a patient feels, and take the patient’s opinions into serious consideration. The doctor’s response to information disclosed by a patient could influence the patient’s perception about the doctor, the doctor-patient relationship, and their trust in the healthcare team.

Patient autonomy is an extremely important aspect of professional medical practice, whereby doctors should respect the patient’s rights and decisions about their own care and treatment. When deciding on a treatment plan for any disease, doctors need to assess the mental capacity of a patient beforehand to see whether they are suitable for making such decisions. Assessing mental capacity is all the more important for patients with anosognosia. As discussed previously, patients with anosognosia may refuse any treatment or care because they believe that nothing is wrong with them, when in reality something is definitely wrong. Even if a doctor deems the patient’s decision to be unwise, he or she must still respect the decision made. Dealing with anosognosia is tricky. 

To resolve this problem, doctors usually engage the patient in self-evaluation about their own health using interviews or questionnaires to assess the presence of anosognosia. This process may be more complicated when anosognosia is prevalent in certain impairments such as motor impairment, because of the possibility that the patient has either explicit or implicit anosognosia.


While anosognosia may not seem like an immediate harm to the patient’s health, it can very well mislead doctors, family members, and the patient themselves to different conclusions about the patient’s condition and clinical needs. Therefore, understanding this condition is helpful for avoiding detrimental errors in clinical practice.

Melle Hsing, Youth Medical Journal 2021


“Anosognosia.” American Psychological Association, Accessed 7 Mar. 2021.

“Anosognosia.” National Alliance on Mental Illness, Accessed 7 Mar. 2021.

Brain scans of schizophrenic patients with low insight and high insight. Treatment Advocacy Center, June 2016, Accessed 26 Mar. 2021.

Cocchini, Gianna & Beschin, Nicoletta & Sala, Sergio. (2012). “Assessing Anosognosia: A Critical Review.” Acta Neuropsychologica. doi: 10. 419-443. 10.5604/17307503.1023693. Accessed 28 Mar. 2021.

Jewell, Tim. “What Is Anosognosia?” Healthline, Accessed 16 Mar. 2021.

“Key Issues of Anosognosia.” Treatment of Advocacy Center, Accessed 26 Mar. 2021.

McLean, Brendan. “The Difficulty in Seeing Your Own Illness.” National Alliance on Mental Illness, Accessed 16 Mar. 2021.”What Is Anosognosia?” Treatment Advocacy Center, Accessed 16 Mar. 2021.

Health and Disease

Is Aging a Disease?

By Melle Hsing

Published 3:37 PM EST, Thurs February 25, 2021


Aging is a phenomenon that everyone experiences with every millisecond that passes. Many believe that the joy of living comes with a natural cost — a slowly degrading body. After all, it is logical to think based on the second law of thermodynamics that the longer we use our bodies, the more damage we accumulate until death. This belief also stems from what is called physiological aging. While chronological aging is simply the increase in the number of living years since birth, physiological aging refers to the decline in the body’s functionality. But given the profound biomedical research on aging in recent years, extending one’s quality of life does not seem like an impossible task for the future. What if scientists could slow down or reverse physiological aging? Would significantly increasing healthspan necessarily extend maximum lifespan?

Aging as a Disease and Diseases of Aging

To view aging as a disease would be to suggest that aging is treatable. However, many gravitate towards the notion that aging is a natural process, conceptualized by the Greek physician Galen. He argued that “aging is universal” (simply put), hence it is not a disease. Bio-demographers also agree that classifying aging as a disease would unjustly reduce numerous age-related diseases (ie. hypertension, osteoporosis, dementia) down to a single vague term, consequently oversimplifying the intricate and key discrepancies between each condition. But universality does not equate to normality, nor does the term “aging” generally assume the consequences of aging. Yes, aging may be a noun that groups a variety of diseases together, however aging itself may still have several unknown causes. 

Giving aging the “disease” label holds medical significance. Doctors and biomedical researchers alike can strive for a cure for suffering elderly patients as soon as possible instead of excusing age-related diseases as inevitable parts of aging and thus only treating the symptoms but not the root causes. David Sinclair, a geneticist at the forefront of aging research, believes that this label will also influence organizations to invest in biomedical aging research. 

Just as living organisms share different functions of life, living organisms may share certain hallmarks of aging. The Cell journal lists the nine hallmarks that are especially relevant to mammals: “genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered intracellular communication”. These hallmarks largely revolve around mechanisms at the molecular and cellular level of aging to infer typical observations of aging on an organismic level such as wrinkled skin and greying hair. Even with a seemingly narrow scope of aging research, scientists have formulated many theories that try to explain the hallmarks of aging, some of which have been modified or rejected. Some of these theories are described below.

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Figure 1: The Nine Hallmarks of Aging

Theories of Aging and Their Implications

The free-radical theory proposed by Denham Harman states that the accumulation of oxidative cellular damage from aerobic respiration causes aging. Aerobic respiration mostly takes place in the mitochondria of eukaryotic cells under oxygen-sufficient conditions. When mitochondria synthesize ATP as an energy source for the cell, they also produce free radicals, highly reactive due to their charged nature. In moderation, free radicals can be beneficial to our immune function and signaling. At high levels, oxidative stress damages mitochondrial DNA, the whole cell, and eventually the totality of organs in the body.

While there are studies that support Harman’s idea, he only focuses on oxidative damage in this theory, failing to take  into account a variety of processes in DNA, cells, and organs that cause damage too. Instead, looking at harm done to the body as a whole may provide a better scope of explanation for the biomarkers of aging. How do organisms protect themselves against cumulative damage?

Ramazzottius varieornatus, commonly known as a tardigrade or water bear, is an example of an organism that protects its DNA from being damaged in extreme environments. Tardigrades are astoundingly resistant to lethal environments, even in outer space. They are active when exposed to water, but when they are desiccated hydroxyl radicals are produced either from the separation of water molecules or DNA exposure to radiation. This radical damages DNA under normal circumstances, but tardigrades can make a damage suppressor protein (Dsup) which may protect its DNA from the hydroxyl radicals. Their incredible ability to resist damage has allowed them to survive for more than 500 million years. If resistance to DNA damage results in a longer lifespan in tardigrades, perhaps altering the speed of physiological aging by introducing interventions for DNA protection could do the same for humans.

Image result for tardigrades under microscope
Figure 2: R. varieornatus Under a Microscope

The somatic mutation theory of aging places a large emphasis on damage but specifically to mutations of the genetic material in somatic cells. Similar to the free-radical theory, it acknowledges  that accumulated mutations lower the functionality of organs, leading to increased susceptibility of age-related diseases. Nonetheless, the body has its own methods to repair DNA using proteins external to the genome, so do those methods become faulty over time hence fail to prevent cumulative damage or do they merely repair to a small extent? If the former is true, what is causing them to go wiry?

Sinclair argues in his book “Lifespan” that aging is the result of accumulated “epigenomic noise”, known as the information theory of aging. The epigenome regulates gene expression by instructing histones in nucleosomes to coil or loosen DNA. By switching on and off certain genes, the epigenome can control cell differentiation. 

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Figure 3: Histones and DNA in Eukaryotic Chromosomes

Environmental factors such as radiation or toxic chemicals in the air may induce DNA mutations, eventually leading to genome instability over time. The epigenome is left to re-establish genomic stability which becomes more and more difficult as mutation rate increases due to constant assaults in the environment. Eventually, the epigenome loses control over gene expression and differentiated cells lose their identity, turning into senescent cells. Cellular senescence in turn leads to diseases such as Alzheimer’s.

Logically, by restoring epigenetic regulation, an organism can build resistance to DNA damage. This idea may seem simple but application is often easier said than done. Scientists have used the information theory of aging to test the extent to which epigenetic activity can be naturally or artificially changed in order to slow down aging or even extend healthspan, with some progress in research. The discovery of key transcription factors such as sirtuins found in humans and the supplementation of nicotinamide adenine dinucleotide (NAD+) brings hope for future treatments. 

Ethical Considerations

Anti-aging research is controversial because current understanding of aging may not be the same for everyone. Some still consider aging a natural process just like Galen did, but some believe that aging is a disease like the many diseases that can be treated. 

There is also the fear that new knowledge can pull humans further away from rationality by overexerting control over what people previously thought was an inevitable part of life. But at the same time, it is arguably rational if not altruistic for people to find ways to prolong healthspan and lifespan. After all, who wouldn’t want to live a longer life of less pain? 

Another problem is the biased convenience of future treatment. Assuming that the scientific community implements anti-aging interventions to extend healthspan, who is to decide who gets the treatment? Simply letting privileged people receive treatment puts the underprivileged at a further disadvantage, creating more inequality between the rich and poor. This bioethical concern becomes even more problematic for the values of the medical community when taking the clinical needs of patients into account, irrespective of their financial situation.


This topic entails philosophical thought to an unsurprisingly great extent because it questions how we understand the process of living. For example, one may ask whether health is inextricably linked to death, or whether a person can pass away having lived a healthy life assuming they do not encounter accidents. Perhaps biomedical research is a test of philosophical ideas which may very well translate into tangible actions that change the course of human nature. Such is the ambitious research done in anti-aging. 

Individuals should not think that the definition of aging is set in stone, because research can contribute many surprising insights into the reality of this phenomenon especially during technological advancement. Given the studies performed by many scientists from the 90s to the 21st century and the theories that suggest causes of aging, there is strong justification for aging to be considered a disease because it may very well be treatable.

With or without research, it is important to remember that aging is relevant to every human being regardless of the scope in which it is viewed. There is no reason to think that only scientists are able to change the way individuals age when life depends on the lifestyle one chooses to live.

Melle Hsing, Youth Medical Journal 2021


“4.3D: Mitochondria.” LibreTexts,

Adam, David. “What If Aging Weren’t Inevitable, but a Curable Disease?” MIT Technology Review, 19 Aug. 2019,

Bulterijs, Sven et al. “It is time to classify biological aging as a disease.” Frontiers in genetics vol. 6 205. 18 Jun. 2015, doi:

Clemson, Lindy, et al. “Free-Radical Theory of Aging.” Encyclopedia of Behavioral Medicine, 2013, pp. 816-17, doi:

Epigenetics in the Central Nervous System.

Faragher, Richard G A. “Should we treat aging as a disease? The consequences and dangers of miscategorisation.” Frontiers in genetics vol. 6 171. 14 Jul. 2015, doi:

“Free Radicals, Antioxidants in Disease and Health.” International Journal of Biomedical Science, vol. 4, no. 2, june 2008, pp. 89-96,