Impaired awareness of illness: Anosognosia

By Dr. E. Fuller Torrey

SUMMARY: Impaired awareness of illness (anosognosia) is a major problem because it is the single largest reason why individuals with schizophrenia and bipolar disorder do not take their medications.  It is caused by damage to specific parts of the brain, especially the right hemisphere.  It affects approximately 50 percent of individuals with schizophrenia and 40 percent of individuals with bipolar disorder.  When taking medications, awareness of illness improves in some patients.
Impaired awareness of illness is a strange thing.  It is difficult to understand how a person who is sick would not know it.  Impaired awareness of illness is very difficult for other people to comprehend.  To other people, a person’s psychiatric symptoms seem so obvious that it’s hard to believe the person is not aware he/she is ill.  Oliver Sacks, in his book The Man Who Mistook His Wife for a Hat, noted this problem:

It is not only difficult, it is impossible for patients with certain right-hemisphere syndromes to know their own problems …And 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.

What is impaired awareness of illness?

Impaired awareness of illness means that the person does not recognize that he/she is sick. The person believes that their delusions are real (e.g. the woman across the street really is being paid by the CIA to spy on him/her) and that their hallucinations are real (e.g. the voices really are instructions being sent by the President). Impaired awareness of illness is the same thing as lack of insight. The term used by neurologists for impaired awareness of illness is anosognosia, which comes from the Greek word for disease (nosos) and knowledge (gnosis). It literally means “to not know a disease.”

How big a problem is it?

Many studies of individuals with schizophrenia report that approximately half of them have moderate or severe impairment in their awareness of illness. Studies of bipolar disorder suggest that approximately 40 percent of individuals with this disease also have impaired awareness of illness. This is especially true if the person with bipolar disorder also has delusions and/or hallucinations.

Is this a new problem?  I’ve never heard of it before.

Impaired awareness of illness in individuals with psychiatric disorders has been known for hundreds of years. In 1604 in his play “The Honest Whore,” playwright Thomas Dekker has a character say: “That proves you mad because you know it not.” Among neurologists unawareness of illness is well known since it also occurs in some individuals with strokes, brain tumors, Alzheimer’s disease, and Huntington’s disease.  The term anosognosia was first used by a French neurologist in 1914. However in psychiatry impaired awareness of illness has only become widely discussed since the late 1980s.

Is impaired awareness of illness the same thing as denial of illness?

No. Denial is a psychological mechanism which we all use, more or less. Impaired awareness of illness, on the other hand, has a biological basis and is caused by damage to the brain, especially the right brain hemisphere. The specific brain areas which appear to be most involved are the frontal lobe and part of the parietal lobe.

Can a person be partially aware of their illness?

Yes. Impaired awareness of illness is a relative, not an absolute problem. Some individuals may also fluctuate over time in their awareness, being more aware when they are in remission but losing the awareness when they relapse.

Are there ways to improve a person’s awareness of their illness?

Studies suggest that approximately one-third of individuals with schizophrenia improve in awareness of their illness when they take antipsychotic medication. Studies also suggest that a larger percentage of individuals with bipolar disorder improve on medication.

Why is impaired awareness of illness important in schizophrenia and bipolar disorder?

Impaired awareness of illness is the single biggest reason why individuals with schizophrenia and bipolar disorder do not take medication. They do not believe they are sick, so why should they?  Without medication, the person’s symptoms become worse. This often makes them more vulnerable to being victimized and committing suicide. It also often leads to rehospitalization, homelessness, being incarcerated in jail or prison, and violent acts against others because of the untreated symptoms.

Studies Correlating Anosognosia with Violence

Lack of awareness of being ill is present in up to 50 percent of those with untreated schizophrenia and up to 40 percent of those with untreated bipolar disorder. It may be a form of anosognosia, damage caused to a certain area of the brain. Anosognosia has been corroborated and “photographed” using structural MRI, functional MRI, single photon emission computed tomography (PET), diffusion tensor imaging (DTI), and other techniques.[1]  MRIs show better brain activation in the insula and the inferior parietal lobule (top) and medial prefrontal cortex (bottom) in schizophrenia patients with high insight as compared to schizophrenia patients with low insight.[2] However, as Dr. Robert Liberman has pointed out, “in all such studies there is considerable overlap in the normal and abnormal ratings.” Conclusions are sometimes drawn from these brain imaging studies that are not warranted.[3]


In comparison with patients with altered insight, those with preserved insight showed significant increased perfusion in the bilateral precuneus. (Catherine Faget-Agius, Laurent Boyer, Romain Padovani, et al., “Schizophrenia With Preserved Insight is Associated with Increased Perfusion of the Precuneus,” Journal of Psychiatry of Neuroscience 37, no. 5 (September 2012): 297–304, (accessed December 25, 2016).

Over two hundred studies document lack of insight.[4] Following are some of the studies showing the association between lack of insight (likely anosognosia) and violence as compiled by the Treatment Advocacy Center:

<BL>· In Ohio, 115 people with schizophrenia who had committed violent acts for which legal charges were incurred were compared to 111 individuals with schizophrenia who had no history of violent acts. The violent individuals had “marked deficits in insight” and were much more symptomatic. Compared to the nonviolent individuals, those who had been violent scored significantly lower on awareness of mental disorder, awareness of achieved effect of medications, and awareness of social consequences of mental disorders.[5]

  • In North Carolina, 331 “severely mentally ill” individuals who had been involuntarily admitted to a psychiatric hospital were assessed for their history of assaultive and violent behavior. The findings indicated “that substance abuse problems, medication noncompliance, and low insight into illness operate together to increase violence risk.”[6]
  • In New York, sixty male patients with psychosis who had been charged with a violent crime were assessed. Severity of community violence was strongly associated with poor insight, medication nonadherence, and substance abuse.[7]
  • In England, forty-four male inpatients in a forensic psychiatric hospital were assessed for violent behavior. It was found that “a previous diagnosis of mental illness, lack of insight, and active signs of mental illness were the most predictive of inpatient violence.”[8]
  • In Spain, sixty-three people with a diagnosis of schizophrenia or schizoaffective disorder were assessed for violent behavior during their brief hospitalizations. The strongest predictors of violent behavior were lack of insight into symptoms (especially delusions), being sicker, and past history of violence.[9]
  • In Sweden, forty “mentally disordered” individuals with a history of “violent criminality” were discharged from two forensic hospitals and followed for between three and twelve years. Twenty-two of them committed additional violent crimes, and eighteen did not. Among the strongest predictors of those who committed additional violent crimes were lack of insight and “noncompliance with remediation attempts.”[10]
  • In England, 503 patients in two forensic psychiatric hospitals were assessed for aggressive and violent behavior. Lack of insight strongly correlated with higher levels of such behavior.[11]
  • In Ireland, 157 individuals with first-episode psychosis were assessed for violent behavior. The strongest predictors of violent behavior in the week following admission were poor insight and a past history of violence.[12]



[1] Treatment Advocacy Center, “The Anatomical Basis of Anosognosia (Lack of Awareness of Illness),” September 2012,–Anatomical_Basis_-_August_2012.pdf (accessed July 25, 2016).

[2] Lisette van der Meer, Annerieke E. de Vos, and Annemarie P. M. Stiekema, “Insight in Schizophrenia: Involvement of Self-Reflection Networks?” Schizophrenia Bulletin 39, no. 6 (November 2013): 1288–95. (accessed July 25, 2016).

[3] For a discussion of overstated claims being made for brain imaging, see Sally Satel and Scott O. Lilienfeld, Brainwashed: The Seductive Appeal of Mindless Neuroscience (New York: Basic Books, 2013).

[4] Xavier Amador, “Anosognosia and Serious Mental Illness,” video, 9:01, June 1, 2011, (accessed July 10, 2016).

[5] P. F. Buckley, D. R. Hrouda, L. Friedman, “Insight and Its Relationship to Violent Behavior in Patients with Schizophrenia,” American Journal of Psychiatry 161, no. 9 (2004): 1712-14. Abstract at (accessed December 24, 2016).

[6] Marvin S. Swartz, Jeffrey W. Swanson, Virginia A. Hiday, “Violence and Severe Mental Illness: The Effects of Substance Abuse and Nonadherence to Medication,” American Journal of Psychiatry 155, no. 2 (1998): 226-31. Abstract at (accessed July 25, 2016).

[7] Nelly Alia-Klein, Thomas M. O’Rourke, Rita Z. Goldstein, et al., “Insight into Illness and Adherence to Psychotropic Medications Are Separately Associated with Violence Severity in a Forensic Sample,” Aggressive Behavior 33, no. 1 (2007): 86-96. Abstract at;jsessionid=A2A18A8D4A27C220186B855F2C5F87D5.f01t04 (accessed July 25, 2016).

[8] Michelle Grevatt, Brian Thomas-Peter, Gary Hughes, “Violence, Mental Disorder and Risk Assessment: Can Structured Clinical Assessments Predict the Short-Term Risk of Inpatient Violence?” Journal of Forensic Psychiatry and Psychology 15, no. 2 (2004): 278-92. Abstract at (accessed July 25, 2016).

[9] Arango Celso, Alfredo Calcedo Barba, Teresa González-Salvador, et al., “Violence in Inpatients with Schizophrenia: A Prospective Study,” Schizophrenia Bulletin 25, no. 3 (1999): 493-503. Abstract at (accessed July 25, 2016).

[10] Strand Susanne, Henrik Belfrage, Goran Fransson, “Clinical and Risk Management Factors in Risk Prediction of Mentally Disordered Offenders–More Important than Historical Data?” Legal and Criminological Psychology 4, no. 1 (1999): 67-76. Abstract at (accessed July 25, 2016)

[11] P. Woods, V. Reed, M. Collin, “The Relationship between Risk and Insight in a High-Security Forensic Setting,” Journal of Psychiatric and Mental Health Nursing 10, no. 5 (2003): 510-17. Abstract at (accessed July 25, 2016).

[12] S. R. Foley, B. D. Kelly, M. Clarke, “Incidence and Clinical Correlates of Aggression and Violence at Presentation in Patients with First Episode Psychosis,” Schizophrenia Research 72, no. 2-3 (2005): 161-68. Abstract at (accessed July 25, 2016).

Peer reviewed studies: Lack of insight

Awareness of Illness in Schizophrenia and Schizoaffective and Mood Disorders

Archives of General Psychiatry 1994 (51): 826-836 Amador XF, Flaum M, Andreasen NC, Strauss DH, Yale SA, Clark CC, & Gorman JM


The study reported in this paper involved over 400 patients from around the country and showed, unequivocally, that poor insight into illness is common in psychotic disorders while being rare in other psychiatric disorders. Large proportions of patients with schizophrenia, schizoaffective disorder, psychotic mania and psychotic depression were generally unaware of having an illness. This study is the first to also evaluate whether patients with these disorders were aware of the signs and symptoms of illness that they personally suffered from. Again, a very large proportion of patients in each of these four groups had no insight into the signs of the illness that they had despite the fact that they had been hospitalized in order to receive treatment for the very same symptoms that they were unaware of. The results of this study make it clear that many patients with these disorders lack the ability to recognize that they are ill and in need of medical care.

The Assessment of Insight in Psychosis

The American Journal of Psychiatry 1993 (150):873-879 Amador XF; Strauss DH; Yale SA; Gorman JM and Endicott J.


This paper reports on a reliability and validity study of a new scale for assessing various aspects of insight into illness.
Five years after the publication of this article, the Scale to assess Unawareness of Mental Disorder (SUMD) has become the most widely used instrument for assessing insight into illness in psychiatric research. It has since been translated into fifteen languages by psychiatric researchers world-wide reflecting a new consensus that the scientific study of insight is possible. The study reported in this paper found that patients with schizophrenia and schizoaffective disorder had pervasive problems with awareness of being ill and that particular aspects of poor insight were strongly correlated with non-adherence to treatment while other aspects of unawareness were not. Similarly, a poorer course of illness and the number of previous hospitalizations were also correlated with various aspects of poor insight.
On the other hand, level of education and level of positive and negative symptoms of the illness were unrelated to insight suggesting that deficits in illness awareness are not a consequence of educational background or simply the byproduct of other symptoms of psychosis. The authors conclude that insight has multiple dimensions than can, and should, be measured reliably. And that deficits in insight are a separate and independent sign of the illness that affects adherence with treatment and the overall course of schizophrenia.

Suicidal Behavior in Schizophrenia and Its Relationship to Awareness of Illness

American Journal of Psychiatry 1996 (153):9, 1185-1188 Amador XF; Friedman JH; Kasapis C; Yale SA; Flaum M & Gorman JM.


Most clinicians believe that poor insight in patients with schizophrenia, though problematic for treatment adherence, may be protective with respect to suicide. The assumption is that patients who do not believe that they are ill are less likely to be suicidal. Alternatively, those patients with schizophrenia who recognize and acknowledge the illness will be more suicidal.
This study found that only awareness of particular symptoms was correlated to increased suicidal thoughts and behavior. Contrary to clinical lore, awareness of having an illness was not associated with increased suicidal thoughts or behavior. Patients who have poor insight into having an illness and are not taking their prescribed medication are just as likely to become suicidal as any other person with schizophrenia.
Estimates are that as many as one out of every ten persons with this illness will kill themselves. This study suggests that poor insight into having an illness is not a protective factor as previously believed and argue against the strategy of leaving such patients who refuse treatment to fend for themselves.

Poor Insight in Schizophrenia: Neuropsychological and Defensive Aspects.

Kasapis C, Amador XF, Yale SA, Strauss D, Gorman JM. Schizophrenia Research, 20:123,1996.


This paper reports on a replication of the Young et. al., study which implicated frontal lobe dysfunction in the etiology of poor insight in patients with schizophrenia. The study also investigated the extent to which defensiveness might play a role in such unawareness. The authors (XFA) had previously hypothesized that frontal lobe pathology may account for the severe forms of unawareness frequently seen in certain psychotic disorders. This study tested this hypothesis using the same neuropsychological tests and insight scale used by Young and his colleagues. Defensiveness was measured using the Balanced Inventory of Desirable Responding (BIDR). The results indicated that defensiveness was modestly correlated with only a handful of the different measures of poor insight. On the other hand, the neuropsychological test results were nearly identical to that of Young and colleagues, indicating that poor performance on tests of frontal function predicted poor insight independent of other cognitive functions tested including IQ. This independent replication adds further evidence in support of the idea that poor insight into illness and resulting treatment refusal stem from a mental defect rather than defensiveness or informed choice.

Psychosocial Treatment Compliance in Schizophrenia.

Lysaker PH; Bell MD; Milstein R; Bryson G & Beam Goulet J. Insight and Psychiatry, Vol. 57, November 1994.


Unlike most studies of insight in the chronic mentally ill, this study evaluated patients when stabilized and enrolled in an outpatient work rehabilitation program. Patients with schizophrenia and schizoaffective disorder with poor insight had very poor adherence to the psychosocial treatment they had agreed to participate in despite a stated desire to work. Poorer insight was also correlated with lower scores on a test of frontal lobe function and with poorer performance on tests of other cognitive functions. The authors conclude that individuals with schizophrenia and poor insight have more problems remaining in a course of treatment regardless of whether it is pharmacologic or a psychosocial treatment they had expressed a desire to participate in. These data, like that of Young et. al., and Kasapis and colleagues, suggest that it is a mental defect that leads to lack of adherence with both pharmacologic and psychosocial treatments.

Insight and the Clinical Outcome of Schizophrenic Patients.

McEvoy JP, Freter S, Everett G, Geller JL, Appelbaum PS, Apperson LJ & Roth L. (1989). Journal of Nervous and Mental Disease, 177(1): 48-51.


Patients with schizophrenia were followed from 2 ½ to 3 ½ years after discharge from the hospital. Although symptoms of psychosis improved in nearly all of the patients over the course of the initial hospitalization, improvement in insight was seen only in those patients who had voluntarily agreed to being hospitalized. Patients who had been involuntarily committed to the hospital did not show a similar improvement in level of insight into the illness. Furthermore, the low levels of insight persisted throughout the follow up period only in those patients who had been involuntarily admitted to the hospital. Not surprisingly, these same patients were more likely to be involuntarily committed over the course of follow up. The authors conclude that an inability to see oneself as ill seems to be a persistent trait in some patients with schizophrenia and one that leads to involuntary commitment.

Insight and its Related Factors in Chronic Schizophrenic Patients: A preliminary Study.

Takai A; Uematsu M; Ueki H, Sone K and Kaiya Hisanobu.European Journal of Psychiatry, 6:159-170, 1992.


Lack of insight into having an illness, defined by a single item on the Present State Examination, was correlated with structural brain abnormalities. Specifically, patients with poor insight into having an illness had increased ventricular brain rations. Ventricular enlargement of the third ventricle was most strongly correlated with poor insight. Meanwhile, IQ was not found to be significantly associated with insight suggesting that the brain dysfunction underlying this deficit in self awareness may be relatively specific rather than a consequence of a general decline in cognitive function. This study is the first to show an association between structural brain abnormalities and lower levels of insight in patients with chronic schizophrenia. It adds to the growing body of literature that suggests that poor insight in this disorder is a consequence of a mental defect.

Unawareness of Illness and Neuropsychological Performance in Chronic Schizophrenia.

Young DA; Davila R & Scher H. Schizophrenia Research, 10:117-124, 1993


This study reports on data that implicates frontal lobe dysfunction in the etiology of poor insight in patients with chronic schizophrenia. Previous authors had hypothesized that frontal lobe pathology may account for the severe forms of unawareness frequently seen in certain psychotic disorders (see recommended review article: Amador et al., 1991). Young and his colleagues tested this hypothesis using neuropsychological tests and the Scale to assess Unawareness of Mental Disorder. The results indicated that poor performance on tests of frontal function predicted poor insight independent of other cognitive functions tested including IQ. These results lend important support to the idea that poor insight into illness and resulting treatment refusal stem from a mental defect rather than informed choice.

Further Parameters of Insight and Neuropsychological Deficit in Schizophrenia and Other Chronic Mental Disease.

Young DA; Zakzanis, KK; Baily C;. Davila R; Griese J; Sartory G & Thom A. Journal of Nervous and Mental Disease, 186, 44-50. 1998. Summarized by Dr. Xavier Amador


This recent study of 108 patients with schizophrenia, found, once again, strong correlations between various tests of frontal lobe function and level of insight. Using the Scale to assess Unawareness of Mental Disorder (SUMD), Young and his colleagues found significant correlations between percent of perseverative errors on the Wisconsin Card Sort Test and overall awareness of illness and attributions for specific symptoms as measured by the SUMD. In this study bipolar patients were also examined using the same methodology, however no significant associations between the insight measure and tests of frontal lobe performance were found. These results replicate previous findings that support the idea that poor insight into illness and resulting treatment refusal stem from a mental defect rather than informed choice in patients with schizophrenia.

Awareness of Illness in Schizophrenia.

Schizophrenia Bulletin, 17:113-132, 1991. Amador XF; Strauss DH; Yale SA & Gorman JM.

This paper reviews the extant literature on insight into illness in schizophrenia. The authors argue for a reassessment of the problem and consensus on terminology and measurement with the stated goal of stimulating scientific research. Furthermore, they argue that poor insight in patients with schizophrenia may be due to brain dysfunction. They point out numerous similarities between poor insight in patients with schizophrenia and anosognosia (a neurological syndrome characterized by unawareness of illness) in neurological patients. They conclude by offering guidelines for terminology and research.

Lack of Insight in Psychotic and Affective Disorders : A Review of Empirical Studies.

Harvard Review of Psychiatry, May/June: 22-33, 1994.

This paper reviews the literature on insight in affective psychoses. The authors remark that relatively little work has been done with this patient group when compared to patients with schizophrenia. Nevertheless, as in schizophrenia, studies of affective disorders find that lower levels of insight are correlated with a poorer course of illness, lack of adherence to treatment and involuntary hospitalizations. The authors also conclude that level of insight is also a trait, unrelated to other signs of illness, in many patients.

Insight and Psychosis. Edited Book

Amador XF & David A, Eds. , Oxford University Press, 1997.

In this book the neurological basis of deficits in illness awareness is the focus of several chapters. In addition, data indicating that lower levels of insight are associated with poorer illness course, increased exacerbations of illness, greater number and longer duration of hospitalizations and non adherence to treatment are reviewed. The role poor insight might play in violent behaviors is also discussed at length.