Exhibit A: A committee of badly disguised Bob Dylan imposters?
As a child, with “Maggies’ Farm” on the record player, I asked an elder sibling why Bob Dylan looked so different on each of his (vinyl) album jackets. She calmly lied through her teeth, and explained that Bob Dylan was a committee, not a single person, and that’s why he looked different on each album — they never got the disguise just right. For about -oh, about an hour – I misinterpreted Bob Dylan’s intent as trying to be sneaky – the committee trying to avoid detection by suddenly changing styles. (Swivelchair won’t fall for that one, again, but still, he does look different. . .) Had either one of us actually thought that a single Bob Dylan was really a committee of badly disguised Bob Dylan imposters, it might have signaled a delusional misidentification syndrome, such as Fregoli delusion or Capgras syndrome.
For failure to properly interpret the intent of others, Pavlova et al. (below) found that (to oversimplify) the right temporal cortex is a little bit unplugged from the rest of the brain:
. . .For the first time, we show that the severity [of deficits] of the right temporal PVL [periventricular white matter] can serve as a predictor of the ability for perception and understanding of others’ actions. We assume that impairments in this ability in PVL patients are caused by disrupted brain connectivity to the right temporal cortex, a key node of the social brain. . .
The other paper I found interesting on this, Seiferth et al. (below) show that people at risk for psychosis have a higher brain activation response when shown a neutral face, (as compared to those not at risk for psychosis.) The have negative attributional bias — interpreting neutral actions as threatening.
This misinterpretation of the intent of others can be seen in the art of Louis Wain — who made cat portraits look progressively more menacing as he became progressively more psychotic:
(The patterns are seen in migraines, and discussed by Oliver Sacks, in the NYT here. ) Just to add to the confusion, an ER room doc once told me that he had an elderly patient who was hallucinating with visual hallucinations — and he had been pretty much blind for 25 years. (The man was otherwise totally sane — just very worried about the visual hallucinations — and there were no auditory hallucinations).
Delusional misidentification syndromes involve the mismatch between people (but occasionally objects) and their emotional or cognitive significance. The result is sometimes an explicable attributional bias — refusal to acknowledge a child, because you’re convinced they’re an imposter, or believing a single person is actually a group of people who put on a disguise (like the Bob Dylan example, above, sort of).
Fregoli delusion is where you think a group of people are actually a single person in different disguise. Here is a case where a single individual though that he and a female friend were in a single body (as described by Mulholland et al. (below)):
A 44-year-old man presented with an unusually colourful and complex form of delusional misidentification. He demonstrated Fregoli syndrome, environmental reduplication and the delusional belief that he and a female friend had been incorporated into the same body. This latter phenomenon has not been described before and adds a new dimension to the rich variety of these syndromes. It is suggested that the term ‘delusional hermaphroditism’ be used to describe this form of delusional misidentification.
There were some articles about how people seeking sex-change operations may be suffering from this type of delusion, and because they can go back and forth between the delusion and their true gender, they are better off not becoming transgendered unless there is a clear basis for that.
Capgras syndrome is where you think someone who looks like someone you know is really an impostor. Prosopagnosia may be an incomplete form of Capgras — in that you can’t recognize individuals, although there is indication that there is an unconscious recognition of the person (because of skin conductance or other measures of emotional response). In rare forms of synesthesia people give sounds a personality — ordinal linguistic personification.
Misidentification delusions can also be dangerous for children who are the object of the misidentification — there are many reported cases of parents killing their children because of misidentification (Aziz et al. below).
At some level, I think paranoid delusions are a form of misidentification delusions — ascribing a threatening intent because that makes cognitive sense inside the delusional scheme — once you’re delusional, then a whole other set of reasoning comes in, which follows logically if you accept the delusion as the premise.
Lee et al., below, report white matter changes are associated with misidentification delusions in Alzheimer’s dementia patients. But, the white matter changes are not associated with paranoid delusions. So that seems to me that with misidentification delusions, the delusion is the dangerous part — the intake of environmental information. The reasoning is not (or not automatically) damaged. You have good reasoning, just that you’re operating in your own delusion.
This is the same basis for anosognosia — people fail to have insight into their illness. (See my post about the Unibomber, Dr. Kazynski , here). He had no insight into his illness, but operating on that delusional premise, he had logical reasoning.
SEIFERTH, N., PAULY, K., HABEL, U., KELLERMANN, T., JONSHAH, N., RUHRMANN, S., KLOSTERKOTTER, J., SCHNEIDER, F., KIRCHER, T. (2008). Increased neural response related to neutral faces in individuals at risk for psychosis. NeuroImage, 40(1), 289-297. DOI: 10.1016/j.neuroimage.2007.11.020
Pavlova, M., Sokolov, A.N., Birbaumer, N., KrÃ¤geloh-Mann, I. (2008). Perception and Understanding of Others’ Actions and Brain Connectivity. Journal of Cognitive Neuroscience, 20(3), 494-504. DOI: 10.1162/jocn.2008.20.3.494
Mulholland, C., O’Hara, A.G. (1999). An Unusual Case of Delusional Misidentification: ‘Delusional Hermaphroditism’. Psychopathology, 32(4), 220-224. DOI: 10.1159/000029093
Aziz, M.A., Razik, G.N., Donn, J.E. (2005). Dangerousness and Management of Delusional Misidentification Syndrome. Psychopathology, 38(2), 97-102. DOI: 10.1159/000085351
Lee, D.Y., Choo, I.H., Kim, K.W., Jhoo, J.H., Youn, J.C., Lee, U.Y., Woo, J.I. (2006). White Matter Changes Associated With Psychotic Symptoms in Alzheimer’s Disease Patients. Journal of Neuropsychiatry, 18(2), 191-198. DOI: 10.1176/appi.neuropsych.18.2.191