Hallucinations

1. My own favorite definition is that given by William James in his 1890 Principles of Psychology: “An hallucination is a strictly sensational form of consciousness, as good and true a sensation as if there were a real object there. The object happens to be not there, that is all.” Many other researchers have proposed their own definitions, and Jan Dirk Blom, in his encyclopedic Dictionary of Hallucinations, includes dozens of these.

2. We cannot be certain whether other animals have hallucinations, although “hallucinatory behaviors” have been observed in laboratory animals as well as in natural settings, as Ronald K. Siegel and Murray E. Jarvik described in their review of the subject.

3. La Barre provided an extended review of anthropological perspectives on hallucination in a chapter published in 1975.

1. Silent Multitudes: Charles Bonnet Syndrome

One day late in November 2006, I got an emergency phone call from a nursing home where I work. One of the residents, Rosalie, a lady in her nineties, had suddenly started seeing things, having odd hallucinations which seemed overwhelmingly real. The nurses had called the psychiatrist in to see her, but they also wondered whether the problem might be something neurological — Alzheimer’s, perhaps, or a stroke.

When I arrived and greeted her, I was surprised to realize that Rosalie was completely blind — the nurses had said nothing about this. Though she had not seen anything at all for several years, she was now “seeing” things, right in front of her.

“What sort of things?” I asked.

“People in Eastern dress!” she exclaimed. “In drapes, walking up and down stairs … a man who turns towards me and smiles, but he has huge teeth on one side of his mouth. Animals, too. I see this scene with a white building, and it is snowing — a soft snow, it is swirling. I see this horse (not a pretty horse, a drudgery horse) with a harness, dragging snow away … but it keeps switching.… I see a lot of children; they’re walking up and down stairs. They wear bright colors — rose, blue — like Eastern dress.” She had been seeing such scenes for several days.

I observed with Rosalie (as with many other patients) that while she was hallucinating, her eyes were open, and even though she could see nothing, her eyes moved here and there, as if looking at an actual scene. It was that which had first caught the nurses’ attention. Such looking or scanning does not occur with imagined scenes; most people, when visualizing or concentrating on their internal imagery, tend to close their eyes or else to have an abstracted gaze, looking at nothing in particular. As Colin McGinn brings out in his book Mindsight, one does not hope to discover anything surprising or novel in one’s own imagery, whereas hallucinations may be full of surprises. They are often much more detailed than imagery, and ask to be inspected and studied.

Her hallucinations, Rosalie said, were more “like a movie” than a dream; and like a movie, they sometimes fascinated her, sometimes bored her (“all that walking up and down, all that Eastern dress”). They came and went, and seemed to have nothing to do with her. The images were silent, and the people she saw seemed to take no notice of her. Apart from their uncanny silence, these figures seemed quite solid and real, though sometimes two-dimensional. But she had never before experienced anything like this, so she could not help wondering: was she losing her mind?

I questioned Rosalie carefully but found nothing suggestive of confusion or delusion. Looking into her eyes with an ophthalmoscope, I could see the devastation of her retinas but nothing else amiss. Neurologically, she was completely normal — a strong-minded old lady, very vigorous for her years. I reassured her about her brain and mind; she seemed, indeed, to be quite sane. I explained to her that hallucinations, strangely, are not uncommon in those with blindness or impaired sight, and that these visions are not “psychiatric” but a reaction of the brain to the loss of eyesight. She had a condition called Charles Bonnet syndrome.

Rosalie digested this and said she was puzzled as to why she had started having hallucinations now, after being blind for several years. But she was very pleased and reassured to be told that her hallucinations represented a recognized condition, one that even had a name. She drew herself up and said, “Tell the nurses — I have Charles Bonnet syndrome.” Then she asked, “Who was this Charles Bonnet?”