Can Anosognosia Help Explain Some Public Acts of Violence?

Failing to know yourself

Posted Apr 25, 2018

Anosognosia has been traditionally discussed when explaining why patients with Alzheimer’s disease (Perrotin et al., 2005), Schizophrenia (Gerretsen et al., 2015), and various lesions (Moro et al., 2016) have resulted in the patient lacking awareness of the functional deficits associated with their disease or affliction. There are two competing models to explain anosognosia; a psychological model, which claims the individual is protecting themselves from the stress caused by their disease, and a neurological model, which posits that the lack of the patient’s insight into their own disorder is due to a failure of neurocognition (Lehrer & Lorenz, 2014). However, both models are in agreement that it is the disease that results in anosognosia: The disease results in the patient not recognizing they have the disease – or at least some symptoms of the disease.

Researchers are still vying for a comprehensive neurological profile of this lack of awareness, and even though the diseases and the injuries that are associated with anosognosia are diverse, there is overlap in the parts of the brain that are impacted. Patients with anosognosia have been found to have hypometabolism in the posterior cingulate cortex (PCC) (Perrotin et al., 2015; Therriault et al., 2018; Vannini et al., 2017), hypometabolism in the hippocampus (Vannini et al., 2016), and reduced gray matter in the anterior cingulate cortex (Spalletta et al., 2014). Some studies posit that reduced right hemispheric volume, which could occur through disease atrophy or injury, relative to the left hemisphere, particularly of the angular gyrus, the medial prefrontal cortex, the dorsolateral prefrontal cortex, insula, and anterior temporal lobe, lead to a lack of awareness in schizophrenic patients (Gerretsen et al., 2014).

To date, there appears to be little research on the prospect of anosognosia concomitantly occurring with an empathy or a moral deficit. This is surprising for two reasons. First, the aforementioned brain regions listed above, are also known to be involved in moral decision making (Baron-Cohen, 2012) and empathic responses (Alegria et al., 2016). Second, it is sometimes symptomatic of patients with Alzheimer’s Disease (Liljegren et al., 2016) and Schizophrenia (Del Bene et al., 2016) to behave violently towards others, which means that any anosognosia could extend to a patient’s unawareness of their own harmful behavior.


If an illness or a lesion results in both a loss of empathy or moral decision making, as well as the self-awareness of these, the behavioral intentions of the individual could change. This is extremely dangerous when the deficit is empathy, because empathy helps to inform humans about harmful behavior; if we observe another human in pain, most of us are able to recreate a sense or a feeling of that pain and thus feel that the behaviors and actions that have led to this are wrong. This mechanism can be behind our drive to prevent harmful behaviors and, and cause us to strive to ease the pain of others. If we stop or ease the pain of another individual, we prevent the need for an empathic response, and thus we stop or ease the empathic pain in ourselves.

The presence of an empathic response to seeing others in pain can thus lead to the stymieing of bad behaviors, not necessarily while they are being carried out, but even stopping them before they are carried out. The absence of an empathic response to pain could lead one to have the perception that some harmful behavior is okay, because this person is missing the internal response that would inform them otherwise. Our view of behaviors being right or wrong, due to our empathic response, will also shape our guiding philosophies and worldviews. If we feel that something is right or wrong, we tend to try and understand these feelings by providing a rationale, and this rationale contributes to our own moral code.


Anosognosia involving an empathy deficit could have a profound impact on the person’s life and their choices. Before the onset of anosognosia and the empathy deficit, the person might feel that certain behaviors are wrong, such as assault and violence; with empathy, these behaviors can be understood as deeply destructive, and function to prevent one engaging in them. The onset of anosognosia and an empathy deficit could lead to a person transitioning from feeling that a certain behavior is bad, to amoral or even good behavior.

Our sense of what is normal also informs our moral code and how we should treat others. Most people tend to think of themselves as rational and fair minded (even though some are open to considering the views of others), and so what they think as right or wrong about the world (including behavior) feels true because it has come from a balanced place. If a person was unaware that they had an empathy deficit, they would still consider themselves rational and fair minded, as they don’t recognize a deficit to undermine this view of themselves. This could mean as their moral code is subtly changing due to an absence of empathy, the change feels true, and thus right, further validating their new view of certain behaviors. If they attribute a recently adopted ideology to this shift in their view, the ideology, too, would be further validated.

A cursory glance at any number of manifestos, penned by murderers before they acted, will inform you of how the way they saw the world changed, and finally how this change brought on their actions, which they felt were necessary. A deliberate act of murder is clearly a failure of empathy, and one cannot help wondering if the murderer was even aware of their empathy deficit.


If an empathy deficit is observed in a patient, or individual, it is therefore of the utmost importance to understand if they recognize this deficit. A person who could understand that they have an empathy deficit, even if it’s temporal, could perhaps take measures to ensure they behave in an innocuous manner, through counseling, or through supervision by friends, family, or healthcare professionals.

It is also crucial to know if a person was aware of an empathy deficit before they acted destructively towards others, because it introduces accountability when the suspect is tried. In some cases of homicide, if mental illness, disorder, or mental illness is suspected, the prosecution often has to argue against a defense that claims the defendant was not accountable due to temporary or permanent insanity, or the defendant acted in a way that was out of their control, because of a clinical difference in brain or mental functioning. If it can be shown that the defendant was aware of their empathy deficit, the legal system could hold them accountable for their actions.

Jack Pemment © 2018


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