Hallucinations in medical context

My grandmother had hallucinations every day for the last 20 years of her life. She imagined ghostly figures walking beside her, saying things that she could barely comprehend, though the tone was often threatening. Fortunately, she found a very pragmatic doctor who simply said, “Well, why don’t you talk back and tell them to go away?” Which she did, with at least modestly successful results.

Oliver Sacks’ latest book, “Hallucinations,” suggests that my grandmother was extremely lucky in her choice of doctor. Sacks describes an experiment from 1973 in which eight “pseudopatients” with no history of mental illness presented themselves at various hospitals across the United States and complained of hearing voices. All except one were diagnosed as having schizophrenia — the other with “manic depressive psychosis.” All were hospitalized, for as long as two months in one case, and no member of staff ever saw through them, though the other “real” patients did.

Sacks’ point here is that hallucinations, of whatever kind, are often regarded by doctors, as well as laymen, as indications or even proof of insanity. It emerges quite clearly, and reassuringly, from his book, that this is rarely the case. Hallucinations, Sacks tells us, are a medical symptom much like any other, by no means always malign, and far more common than most of us would suppose.

By the end of the book I felt I’d been missing out since my experience of hallucinations is limited to the visual patterns connected with migraine. Still, many possibilities lie ahead: Hallucinations are associated with all kinds of ailments, not least Parkinsonism and Alzheimer’s disease.

Sacks is a serious, hugely knowledgeable, experienced and compassionate doctor, but he’s writing for the general reader here, and like the rest of us he’s drawn to the more extreme and startling cases. Hallucinating the smell of pipe tobacco may be strange enough but it doesn’t seem so outlandish when compared with cases where individuals hallucinate a doppelganger of themselves and are able to interact with it: Heautoscopy is the technical term. Deja vu is a common phenomenon, but how many of us have experienced (or even heard of) jamais vu?

Sacks’ scope is both general and particular. The broader topics he deals with include phantom limbs, out-of-body experiences, delirium tremens, post-traumatic stress disorder, “hauntings,” ecstatic or religious hallucinations and epilepsy.

For most of us, the most intriguing chapter in the book is likely to be the one containing an account of Sacks’ own, mostly drug-induced, hallucinations. Sacks’ experiences are so colorful, his reactions so extreme, that you find yourself admiring his sensitivity and fortitude, his willingness to be his own experimental subject.

I can’t help thinking that most readers will be drawn to this book for its freak-show elements rather than to gain a deeper understanding of neurology. The human brain, as Sacks demonstrates, is the freakiest show in town.