Week Four: Hallucinations


Oliver Sacks’ book, Hallucinations, is an investigation into auditory, visual, tactile and olfactory hallucinations, their many guises, their psychological sources and their personal and cultural resonances.

Week Four: Hallucinations
(Image credit: Dianne Harris & Wellcome Images)

Hallucinations usually imply psychosis, but there are many different types of non-psychotic hallucination caused by illness or injury, intoxication - or even just falling asleep. From the elementary geometric shapes we see when we rub our eyes to the complex swirls, blind spots and zigzags of a visual migraine, hallucination takes many forms.

In more extreme cases, hallucinations can be associated with altered states of consciousness that may come from physical or sensory deprivation, or from certain brain disorders, and these can lead to religious epiphanies and conversions or to other forms of extreme belief or behaviour.

Drawing on a wealth of clinical examples from his own patients as well as from historical or literary descriptions, Sacks investigates the fundamental differences and similarities of many kinds of hallucination, what they say about the organisation and structure of our brains, how they have influenced every culture’s folklore and art, and why the potential for hallucination is present in every one of us.

Niall Boyce, Editor at The Lancet Psychiatry and a reader of Sacks’ work since medical school, touches on the significance of storytelling in science writing and how important that skill is when it comes to offering readers a look within themselves whilst discussing a subject such as neuroscience.

True stories: the work of Oliver Sacks

One of the impediments to my career as a doctor was that I had—and continue to have—an appalling memory for faces and names.But stories were a different matter. Once I remembered one aspect of a patient’s history, the rest would come flooding back. Perhaps this is why I have always enjoyed Oliver Sacks’ books: he is one of the few writers to capture the experiential, narrative aspect of science and medicine.

I first came across Sacks’ work almost twenty years ago, when I was at medical school, and trying to get to grips with neuroscience. I had more or less coped with the physiology and anatomy I had learned up to that point: structure and function are pretty easy to relate to one another in, for example, the kidneys or the lungs. The brain was altogether different. How did this creamy, blancmange-like mass produce movement and speech, process information, and generate feelings of love, hate, happiness, and fear? My tutor, with the wisdom and patience that was so necessary when dealing with a student such as I, recommended I read The Man Who Mistook His Wife for a Hat. The effect Sacks achieves in this book is what all science writers should aim for: he does not simply relate facts, but leads us through the maze of the case history such that we feel the diagnostic breakthrough at the end is our own.

To write this way requires considerable scientific knowledge and narrative technique, as well as that rarer quality in an author, humility. These skills are again evident in Hallucinations, but I believe this book is the greater achievement. Sacks’ earlier works can be seen as a safari through the neurological textbook: but in this new volume, he encourages the reader to look within, and to think about his or her inner world, partially through frank descriptions of his own hallucinations. A scientist can understand the fragile nature of experienced reality, but only a storyteller such as Sacks can truly describe it. Sacks’ case histories are not merely entertaining sideshows: they are essential to understanding neuroscience, and hence understanding ourselves.

Niall Boyce
Editor, The Lancet Psychiatry