Anosognosia revisited

Over a decade ago, I noticed a new term cropping up in psychiatry: anosognosia. Actually, it was an old term, coined a century earlier by neurologists to describe a behavioral sign in certain types of brain damage. But by the time I took notice, this mouthful of a word was doing double duty. In neurology it still referred to peculiar deficits of awareness linked to specific anatomical damage in the brain. In psychiatry it began to mean something else.

I wrote a blog post in 2011 on the misuse of “anosognosia” in psychiatry, a word that had come to mean the denial of illness often seen in severe psychiatric disorders. Psychiatry already had a perfectly good phrase to describe this denial: lack of insight. By my reckoning, replacing this with a neurological term was a rhetorical trick, “intended to make psychiatry sound better understood, and more biological/neurological, than it really is.”

Insight is subjective

At the time, I emphasized subjectivity in assessments of insight. This is reflected in the common observation that psychiatric patients have “good insight” if they agree with their psychiatrists, and “poor insight” otherwise. Given the many reasons one might differ with one’s psychiatrist, from delusions to honest conceptual disagreements, “anosognosia” seemed a crude way to pathologize disagreement.

It’s now 2024, and “anosognosia” is alive and well in popular media about mental illness. It’s a word pushed by treatment advocacy groups, less so by psychiatrists. In view of its tenacious foothold, I’d like to revisit this formerly obscure term, with a somewhat different spin than I gave it 13 years ago. It’s not so much the subjectivity of insight I want to emphasize now, but the political use of language.

Neurology uses “anosognosia” precisely

Coined in 1914 by the neurologist Babinski, for a century “anosognosia” meant denial or lack of awareness of disability due to injury or disease of specific parts of the brain.

One example is “hemi-inattention”: lack of awareness of one side of the body, or one side of the visual field, due to parietal lobe damage. For example, a patient with a right-hemisphere stroke may be unaware that his or her left arm is paralyzed. Such a patient, when asked to draw a clock face, may add numbers only to the right side, neglecting the left completely. Or notice a stimulus in the right visual field (of both eyes), but not the left. This is hemi-inattention. Other early examples included cortical blindness and cortical deafness, sensory deficits that the patient may be unaware of, due to damage in the cerebral cortex.

Prior to the invention of brain imaging, e.g., CT scans in the 1970s, neurologists could determine the site of brain damage, most often in the parietal lobe, by the presence of anosognosia. It was, and is, a neuroanatomical localizing sign. One of the special skills of the neurologist is to localize nerve or brain dysfunction by careful assessment of signs and symptoms.

Later, neurologists applied “anosognosia” to lack of awareness of deficits in some types of dementia, due to specific frontal lobe damage. This is again a neuroanatomical localizing sign.

Words can slip in meaning

Unfortunately, the application of this word in dementia may have misled lay observers (and a few die-hard biological psychiatrists) to conclude that lack of illness awareness in schizophrenia and manic psychosis is anosognosia as well.

I should digress here to acknowledge that words, especially psychological words, often change their meanings over time. “Idiot,” “moron,” and “imbecile,” all words that now roughly mean “stupid,” once had precise psychological meanings. “Narcissism” and “gaslighting” have devolved from highly specific terms to general terms of disapproval. If one likewise wants to argue that “anosognosia” once meant something very specific in neurology, but now means general cluelessness or lack of insight, I can’t really say that’s wrong. I can only regret that a once useful word has been dumbed down in the service of political rhetoric.

A veneer of pseudoscience

“Anosognosia” in psychiatry offers nothing more than a veneer of pseudoscience. There’s no evidence that lack of insight in schizophrenia is related in any neurological way to the lack of insight in anorexia nervosa. Yet “anosognosia” has been applied in both. Conversely, patients with ego-syntonic personality disorders also lack insight and deny their illness, but the term is not applied there, because these disorders don’t seem “biological” enough to lay claim to a neurological term.

More fundamentally, there is no neuroanatomical localization in psychiatric disorders — by definition really. As I’ve often noted, whenever a psychiatric condition is localized and understood medically, it inevitably leaves psychiatry, to be claimed by neurology or another branch of medicine. Psychiatry is what’s left. The only thing “anosognosia” adds to “lack of insight” is the implication that (some) “psychiatric disorders are brain diseases.”

As I’ve also repeatedly argued, this is political rhetoric, not science. The reality is far more complicated. Psychiatric disorders differ widely in the degree to which they appear biological, yet even the most biological-seeming have strong psychological components.

Anti-psychiatrists often claim there is no biology in psychiatry at all — that it’s all social control, punishment of deviance, and the like. Conversely, treatment advocacy groups and some biological psychiatrists seem to believe it’s all biology.

False certainty helps no one

Both groups are mistaken. Psychiatry is fundamentally uncertain and in-between. Yes, there’s biology. And yes, there are social factors at play in psychiatric assessment (and functioning) as well. Even in psychosis, a patient’s degree of insight can fluctuate in response to stress and other environmental factors. It’s not, as the neurologists might say, a fixed deficit.

As I wrote 13 years ago, the use of “anosognosia” is a rhetorical device to make insight judgments in psychiatry sound more biological/neurological, without offering any particular reason to do so. This misuses the term, and lays claim to unwarranted certainty in an inherently uncertain domain. Like “chemical imbalance” and other convenient oversimplifications, it’s understandable that untrained laypeople might make this mistake. It’s more disappointing when mental health professionals do, especially when they really should know better and be more honest.