Oliver Sacks is a practicing neurologist and professor of neurology at New York University School of Medicine.* He was born in London but has lived in New York since 1965. He is the author of The Man Who Mistook His Wife for a Hat, and his latest book is Hallucinations.
Tiffany O’Callaghan: Your latest book is about hallucinations. Why did you want to write about them?
Oliver Sacks: I've been fascinated with them for a long time. I've touched on hallucinations in different ways in earlier books, but there's such a vast variety, and there are so many causes, so much misunderstanding—and sometimes so much stigma attached—that I thought it would be good to bring things together. An additional reason has been the beautiful neuroimaging in the last 10 years or so, which confirms that at least simple hallucinations tend to arise in sensory areas which normally serve perception.
TO: You mentioned stigma. Do most people associate hallucinations with mental illness?
OS: I think there's a common view, often shared by doctors, that hallucinations denote madness—especially if there's any hearing of voices. I hope I can defuse or de-stigmatize this a bit. This can be felt very much by patients. There was a remarkable study of elderly people with impaired vision, and it turned out that many had elaborate hallucinations, but very few acknowledged anything until they found a doctor whom they trusted.
There are all sorts of situations in which one may have hallucinations. Many people have hallucinations of a sort before they fall asleep or sometimes just after waking.
TO: What is the difference between hallucination and imagination?
OS: I think you recognize that what you imagine is your own, whereas with hallucinations there is no sense of you having produced them. One feels, "What's that? Where did it come from?"
I saw this very clearly many years ago in an old lady who started to hear Irish songs in the middle of the night. She thought a radio had been left on but couldn't find the radio. She then thought that a tooth filling was somehow acting as a transistor. Finally, when certain tunes kept repeating themselves, all tunes that she knew, she wondered if it was a sort of radio inside her head, a mechanism not under her control, and apparently not related to what she was thinking or feeling or doing. That way of putting things is very common in people with musical hallucinations.
TO: In the book [Hallucinations], you share experiences of your "lost years" in California in the early 1960s, when you tried lots of drugs. Why write about this now?
OS: The primary reason is that what happens with me is a potential source of information. I will, as it were, use my own case history as I will use other people's. But perhaps again the fact that these were encapsulated in a time period, say, between 1963 and 1967, more than 40 years ago, made me feel easier about describing them.
TO: You experimented with LSD and other hallucinogens. Have those experiences informed your work as a neurologist?
OS: I think it made me more open to some of my patients' experiences. For example, there is something which I think of as stroboscopic vision, or cinematic vision, where, instead of seeing a scene continuously, you see a series of stills. I've had that myself on LSD, I've had it in migraine, and my patients taking L-dopa sometimes describe it, too. So rather than saying nonsense, or closing my ears, I am open to these descriptions. Whether these psychedelic drugs made much difference to me otherwise, I don't know. I'm glad I had the experience. It taught me what the mind is capable of.
TO: One time you had a conversation with a spider ...
OS: With the spider, I should have known that it's impossible. That's one of the few times when I was completely taken in. The business of believing and being converted by hallucinations worries me. For example, a book has just been published by a neurosurgeon who had a so-called near death experience and is convinced that he saw heaven. I want to say, strongly, hallucinations aren't evidence of anything, let alone heaven.
TO: You highlight a tendency for hallucinations, particularly those caused by epileptic seizures, to feel like religious experiences. Why is that?
OS: Hallucinations can be very powerful and very persuasive. I think one may have to fight to deny them weight. There was one case history which I should have put in the book. A young woman, a physician, had some of these seemingly revelatory seizures, but she argued with God. God said: "Don't you believe your senses?" She said: "Not when I'm in a seizure."
TO: Is there potential for people to follow commands they are "given" during hallucinations?
OS: It seems probable that Joan of Arc had command hallucinations of a sort. At first these would just present themselves as figures and voices and a light to one side, and only later did she feel these figures were telling her to go and do things.
TO: You also talk about how hallucinations can result from loss of hearing or vision.
OS: Normally, there's a system of checks and balances in the brain, to prevent any particular region taking off autonomously. If one loses these constraints, for example, if one is blind or even blindfolded, then the visual brain may take off on its own and utilize memory and imagination to give one hallucinations. I work especially in old-age homes and see elderly people—I'm now more elderly than many of them—with hearing and visual impairments, but quite clear mentally. I've been struck by their tendency to have hallucinations as the sense of perception is diminished.
TO: You have a visual impairment. Does this influence whether you have hallucinations?
OS: I have low-level hallucinations all the while. I see geometrical patterns and proto-letters everywhere. For example, looking up at the ceiling, as I'm doing now, I see angled forms which look like letters or words. They form and re-form very rapidly. Gradually it's got more pronounced. But I can and do ignore it, just as I ignore my tinnitus, which goes with my deafness. I'm getting like my patients with auditory and visual impairment. I hope there's no mental impairment yet. [Laughs]
TO: Do you worry that sharing your patients' stories somehow exploits them?
OS: I'm on this delicate boundary, and have been for 50 years or so. At one time I was my own prime accuser. Whenever I saw the word portrayal, I would misread it as betrayal. First, in addition to any formal consent, I want to be reassured from what I know of a patient that they won't be upset by anything.
TO: Do you hope that sharing these stories changes people's perceptions?
OS: I feel that if I describe things respectfully, tenderly, and truly, then this is an important thing to do. It's not voyeurism, it's not exploitation, but an essential form of knowledge. I think the detailed case history has no equal in conveying understanding, not only of what a condition is like, but of the ways in which a person may respond to a condition.
I remember when an opera was made from my book The Man Who Mistook His Wife for a Hat, I said to the librettist, you must go and see Mrs. P—the woman who was mistaken for a hat—and see how she would feel about this. I watched her watch the opera, wondering fearfully what she might be thinking. But she came up to me and the librettist and said, you have done honor to my husband. I hope in some sense I can do honor to the patients.
TO: This is your 12th book. Does writing help you make sense of the world?
OS: I often don't feel I've come to terms with an experience unless I have had a go at describing it. This has been an almost lifelong disposition; I have notebooks going back to the age of 14.
This article originally appeared in New Scientist.
Correction, Nov. 13, 2012: This article originally gave an outdated academic affiliation for Oliver Sacks. He is a professor at New York University School of Medicine, not Columbia University.