OUP user menu

CONVERSION HYSTERIA: TOWARDS A COGNITIVE NEUROPSYCHOLOGICAL ACCOUNT.
Edited by Peter W. Halligan and Anthony S. David. 1999. Hove, UK: Psychology Press. Price £24.95. Pp. 292. ISBN 0-86377-651-5.

Dr Adam Zeman
DOI: http://dx.doi.org/10.1093/brain/124.1.232 232-233 First published online: 1 January 2001

Around one-third of the patients attending our clinics prove to have medically unexplained symptoms. Some of these, with especially dramatic complaints, will earn `the diagnosis which dare not speak its name'—hysteria. The path to diagnosis is not always smooth. Every neurologist must have encountered a clinical mystery which is finally dispelled by a highly relevant, and all too often unlooked-for, psychological revelation. Whether we are irritated or intrigued by such cases, competent practice obliges us to do our best to recognize and manage patients whose psychological predicaments are announced by neurological symptoms. The difficulties that we encounter in teasing out the psychological thread partly reflect our training. Few neurologists possess formal psychiatric expertise, with the result, often confusing and counterproductive for our patients, that hysteria is a disorder diagnosed by one hospital team but treated by another.

For similar reasons, I suspect that few of us apply precise criteria to the diagnosis of hysteria. Working backwards from everyday clinical practice one can infer that our implicit criteria must be along the following lines. We entertain the diagnosis of hysteria when we encounter a patient whom we judge to be sincere (and not malingering) with a set of neurological symptoms which lack a neurological basis (so far as we can tell), and for which we suspect a psychological explanation (on more or less firm grounds). The bracketed qualifications point to some of the pitfalls in diagnosis: how confident are we that there is no neurological disorder? Is our patient's psychological distress really the cause of an undiagnosed disorder, or its understandable result? Can we tell whether our patient is the unconscious victim of her symptoms rather than deliberately misleading us?

The essays brought together in this excellent collection are not aimed so much at the clinical dilemmas of hysteria—although these are well summarized in an introductory chapter by Crimlisk and Ron—as at the theoretical and scientific questions which it raises. Three interrelated issues attract much of the authors' attention. (i) The term `conversion' disorder which lives on in the DSM classification of psychiatric disorders, and which refers to the unconscious conversion of psychological distress into physical symptomatology, originates in a Freudian theory of the psyche, which has been largely replaced in other contexts: we need some better way of conceptualizing hysteria. What should it be? (ii) At least some patients with hysteria do appear to be genuinely puzzled by their symptoms, despite our strong reasons for believing that they have a psychological basis. In other words, they are unconscious of the true explanation for their predicaments. They may, in cases of hysterical blindness or anaesthesia, also appear to be unconscious of sensory data of which one would expect them to be vividly aware; in cases of hysterical paralysis they are unconscious of the fact that they `can' in fact move quite normally. If hysteria is in some sense a disorder of consciousness, do any aspects of recent work on consciousness help to illuminate its obscurities—in particular, research on hypnosis, neglect and `implicit' cognitive processes? (iii) The explanation of hysteria is most unlikely to be wholly `biological', but the final common pathway of hysterical symptoms must plainly involve the brain. Can we use modern techniques of investigation, functional imaging and neurophysiology to learn more about the processes at work?

The contributions by Edgar Miller and Sean Spence address the first issue. Miller questions whether `conversion hysteria' is a viable clinical concept. He directs his keenest fire on the assumption, inherent in the diagnosis of hysteria, that `those with hysterical symptoms … experience them as symptoms over which they have no voluntary control (i.e. they are not feigned)'. On the basis of evidence that psychiatrists—like detectives—have great difficulty in detecting experimental dissimulation, and that patients with hysteria often perform indistinguishably from malingerers on systematic testing, he concludes that it is `highly unsatisfactory' to build a judgement that symptoms are not feigned into the concept of hysteria. Sean Spence takes this line of argument a step further: maintaining the motor signs of hysteria appears to require attention, presumably conscious attention: `the paralyses break down when the subject is distracted, consciousness is obtunded or when they are circumvented by reflexive motor routines'. Spence takes these observations to show that hysterical paralyses are disorders of the will to act, rather than unconscious subversions of motor control, quoting Paget's wonderful nineteenth century description of such patients: `… they say, `I cannot'; it looks like `I will not'; but it is `I cannot will' `.

These arguments encourage us to look for alternative conceptualizations of hysteria, as neither arm of the familiar dichotomy between malingering and `unconscious' symptom production seems quite to fit the bill. What are the alternatives on offer? Edgar Miller points to `abnormal illness behaviour' as a promising model. Sean Spence draws attention to two further options: the clinically important possibility that the `abnormal will' in hysterical paralysis is the product of an abnormal conscious mind, derailed by anxiety or depression; and the overlapping possibility that in many cases of hysteria self-deception is at work. Further exploration of these ideas is well worthwhile, but other contributors to this book prefer to pursue the more conventional hypothesis that, somehow or other, the hysterical patient's consciousness of an affected sense, or of her capacity to move, has been disturbed. How could this be?

One thought—not a new one—is that hypnosis might offer a helpful analogy to hysteria. Many, possibly all, of the presentations of hysteria can be reproduced by hypnosis, including paralysis, levitation, blindness, anaesthesia, paraesthesiae and pain. Hypnotic subjects and hysterical patients both claim to experience their symptoms as involuntary intrusions. As Bryant and McConkey outline in their chapter on functional blindness, there is comparable evidence of unacknowledged processing of visual information in hysterical and hypnotic blindness. Similarities like these prompted Babinski to suggest that hysteria should be renamed `pithiatisme', `a condition due to persuasion'. But for our purposes, the limitation of the analogy between these two sets of phenomena is that the nature of hypnosis is at least as controversial as the nature of hysteria. Indeed, to judge by the chapters by Bryant and McConkey and Oakley in this volume, the theory of hypnosis has seen a difference of opinion between two schools of thought which are precisely mirrored in discussions of hysteria, one holding that hypnosis induces a distinctive conscious state, the other holding that it operates through social coercion and role play.

The analogy between hypnosis and hysteria may yet come into its own, as new techniques of investigation are brought to bear, of which more below. But, in the meantime, is there any other help to be had from contemporary thinking about consciousness in other contexts? Sierra and Berrios point to similarities between sensory loss in hysterical anaesthesia and the phenomena of neglect. Both occur in the absence of major damage to sensory pathways, affect the left more often than the right side of the body, and are associated with evidence of unacknowledged sensory processing to a high level. In common with `segmental exclusion syndrome', a syndrome of disuse following trauma or infection, hysterical anaesthesia and neglect may be associated with reduced attentional evoked potentials—although this is controversial.

A third analogy, proposed by Bryant and McConkey, overlaps with the last. They suggest that functional blindness, of both hysterical and hypnotic varieties, involves a dissociation between `awareness and function' of the kind which occurs specifically in subjects with blindsight, and more generally in circumstances in which `implicit' psychological processes survive while `explicit' functions are impaired. This raises an interesting point. In subjects with blindsight, and other preserved `implicit' abilities, we interpret signs of preserved function, in the absence of acknowledged awareness, as evidence for surviving `unconscious' processes. In a patient with hysteria similar evidence of preserved function might easily be interpreted as evidence for deliberate deception. The contrast—and the ambivalence which underlies it—emphasize how imperfectly we understand the processes which generate `awareness'.

The final common theme in these essays is the potential application of new methods of investigation to hysteria. Sierra and Berrios discuss the use of sensory evoked and `cognitive' event related potentials in patients with hysterical sensory loss. Although the evidence is somewhat murky, they conclude that results point to `preserved early sensory processing in the face of altered P300 and selective loss of awareness'. An alternative method is to employ functional imaging to tease apart the processes at work in hysteria. Sean Spence outlines one approach in this volume, which has since led to the report of hypofunction of the left dorsolateral prefrontal cortex in patients with unilateral (left or right) hysterical weakness. Right prefrontal hypofunction was seen, by contrast, in subjects feigning weakness. But these results conflict with other evidence, obtained by a group including Peter Halligan, one of the editors of this volume, for right anterior cingulate and orbitofrontal hyperfunction in one subject with an hysterical left-sided hemiplegia and in another with a similar pattern of weakness induced by hypnosis.

I have so far avoided one factor that is bound to complicate the study of hysteria. It is most unlikely that it represents a unitary disorder. It is immensely varied in its symptoms, in its tempo, in its psychological associations, and its social consequences. A syndrome of transient paralysis at the time of stressful exams in a young student may have a very different psychological and neurological basis to the embedded disability of a middle-aged patient with multiple long-standing unexplained physical symptoms whose livelihood depends entirely on her benefits. It is no surprise that such a varied disorder should generate a variety of hypotheses and results. But David and Halligan's volume broadcasts the excellent news that this common, clinically important, neglected but eminently studiable condition is receiving a fresh wave of attention.