CONVERSION AND DISSOCIATION SYNDROMES

Published on 10/04/2015 by admin

Last modified 22/04/2025

Print this page

This article have been viewed 5640 times

CHAPTER 20 CONVERSION AND DISSOCIATION SYNDROMES

Social historians have confidently asserted that conversion hysteria has disappeared from clinical practice, to be replaced by syndromes characterized by fatigue and other medically unexplained disorders.^1,² Although the florid manifestations of hysteria seen in the days of Pierre Janet are less common in the 21st century, the evidence from clinical practice is that patients with conversion disorders are not infrequently encountered by neurologists in both outpatient and inpatient settings.³ Indeed, it has been shown that symptoms considered “functional,” “psychogenic,” “medically unexplained,” or “hysterical” account for up to one third of new referrals to neurology outpatient departments.^3,⁴ In a German survey, Rief and colleagues⁵ found a 2% base rate of unexplained paralysis or localized weakness in the population and a 5% base rate for “impaired coordination or balance” and “unpleasant numbness or tingling sensations.” In this chapter, the diverse manifestations of conversion and dissociation disorders are described, and the advances in approaches to treatment are outlined.

PROBLEMS WITH DEFINITION

There are a number of problems with the definition of the conversion disorder. First, physical disorder must be excluded, but the rate of neurological comorbidity is known to be high in patients with conversion disorder,⁶ and distinguishing which symptoms are accounted for by organic disease and which are not can be difficult. Second, it is stated that^6a a temporal association between a psychological stressor and the onset on the disorder should be identified, but in practice, this is often impossible to establish, and doing so depends to a large extent on the skill of the interviewing physician. Finally, by definition, the process should be unconsciously mediated, but in practice it is difficult (some authorities would say impossible) to distinguish between symptoms that are not consciously produced and those that are intentionally manufactured. The Diagnostic and Statistical Manual of Mental Disorders, 4th edition,^6a provides no criteria for distinguishing conscious from unconscious intent, and many authors have argued that the criteria of whether the patients are consciously aware of producing these symptoms should be excluded from the diagnosis of conversion disorder.⁷

A question often asked by neurologists, when confronted with a patient with unexplained loss of function of the limb, is “How do I distinguish between conversion disorder, factitious disorder, and malingering?” For the reasons just described, it is difficult to answer this question, because a patient’s “awareness” or “motivations” are not knowable. Various attempts have been made to provide adequate definitions, but all have their limitations (Table 20-1). Attempts to “demedicalize” this complex diagnostic field have introduced the concepts of “free will” and patient choice,⁸ and motor symptoms of hysteria have been discussed as “disorders of willed action.”⁹ Neurologists require considerable skills to diagnose and manage these conditions, which can be among the most taxing in the speciality.¹⁰

TABLE 20-1 Relationships between Conversion Hysteria, Factitious Disorder, and Malingering

The term conversion is conventionally applied to somatic symptoms, whereas if the symptom is psychological (e.g., a loss of memory or an external hallucination) rather than physical (e.g., a loss of power), it is regarded as dissociative. Dissociation has attracted considerable interest, and in a major review of the topic, Holmes and colleagues (2005)¹¹ drew a distinction between two qualitatively distinct, clinically relevant forms of dissociation, labeled compartmentalization (type 1) and detachment (type 2)¹² (Table 20-2). Compartmentalization phenomena are characterized by impairment in the inability to control processes or actions that would usually be amenable to such control and that are otherwise functioning normally. This category encompasses unexplained neurological symptoms (including dissociative amnesia) and benign phenomena such as those produced by hypnotic suggestion. In contrast, detachment phenomena are characterized by an altered state of consciousness associated with a sense of separation from the self, the body, or the world. Depersonalization, derealization, and out-of-body experiences constitute archetypal examples of detachment in this account. Evidence suggests that these phenomena are generated by a common pathophysiological mechanism involving the top-down inhibition of limbic emotional processing by frontal brain systems. Although these two types of dissociation are typically conflated, evidence suggests that different pathological mechanisms may be operating in each case.

TABLE 20-2 Classification of Two Types of Pathological Dissociation

Type 1 Dissociation (Compartmentalization)	Type 2 Dissociation (Detachment)
Conversion disorders	Depersonalization/derealization
Dissociative amnesia	Peritraumatic dissociation
Dissociative fugue	Out-of-body experiences
Dissociative identity disorder	Autoscopy (?)

From Brown RJ: The cognitive psychology of dissociative states. Cogn Neuropsychiatry 2002; 7:221-235.

Support for the compartmentalization model comes from psychophysiological research, which suggests that psychogenic illness is associated with a deficit in attentional, conscious processing and the preservation of preattentive, preconscious processes. According to Brown,¹³ there is very little difference between “negative” symptoms, such as sensory loss and paralysis, and “positive” symptoms, such as tremor and dystonia, in terms of basic underlying mechanisms. According to this view, all symptoms result from a loss of normal high-level attentional control over low-level processing systems; in this sense, all symptoms can be viewed as involving a form of compartmentalization. In each case, the “dissociation” between high- and low-level control results from the repetitive reallocation of high-level attention onto “rogue representations” in memory, causing low-level attention to misinterpret this stored information as an account of current rather than past processing activity. The model is shown diagrammatically in Figure 20-1.

Figure 20-1 The generation of experience and control of action by the cognitive system. This model suggests that the management of behavior is governed by systems that operate without direct volitional control. This is important in that it allows for functional dissociations between the experience of volition and the control of thought and action.

(From Brown RJ: Psychological mechanisms of medically unexplained symptoms: an integrative conceptual model. Psychol Bull 2004; 130:793-812.)

EPIDEMIOLOGY

In 1976, an editorial in the British Medical Journal suggested that hysteria was “virtually a historical curiosity in Britain.”¹⁴ Despite this assertion, the published evidence suggests that it is as common as other disabling conditions such as multiple sclerosis and schizophrenia.¹⁵ In a comprehensive review of the literature, Akagi and House¹⁵ concluded that the lowest prevalence data suggested a rate of about 50 per 100,000 for cases of conversion disorder known to health services at any one time, with perhaps twice that number affected over a 1-year period. These prevalence studies suggest that the burden of disability associated with chronic hysteria is far higher than a typical practicing psychiatrist might expect or than is reflected in standard textbooks of psychiatry or clinical neurology.

CLINICAL FEATURES

Conversion Disorder

Previous Unexplained Symptoms.

There is accumulating evidence that the more unexplained symptoms the patient has, the more likely the primary symptom is to be unexplained.¹⁷ In one study of patients with medically unexplained motor symptoms, additional unexplained symptoms, including paresthesia (65%), pseudo-epileptic seizures (23%), and memory impairment (20%), were reported.¹⁸ It is, therefore, often useful when conversion disorder is being considered as a diagnosis to obtain a printout of the patient’s history from the primary care physician. This may reveal repeated presentations to different specialists, as well as a history of repeated surgical procedures, particularly without clear evidence of pathology.

Psychiatric Comorbidity.

Rates of depression (38% to 50%) and anxiety (10% to 16%) have been identified in a number of studies. In one small prospective controlled study, there was a fourfold increase in depression among patients with conversion disorder in comparison with matched controls with similar organic disability.¹⁹

Recent Life Events or Difficulties.

An increased number of life events in the year preceding symptom onset have been recorded in small controlled studies of unexplained motor symptoms ²⁰ and pseudoseizures.²¹ More recent evidence suggests that when patients are interviewed carefully, some report symptoms of panic just before the onset of, for example, functional weakness (J. Stone, personal communication, 10.2.2006). Judicious questions about sensations of sweating, dizziness, and breathing difficulty may reveal these somatic symptoms of anxiety, which may also be reported before the onset of sensory symptoms (see later section on sensory symptoms).

Secondary Gain/Litigation.

This is a complex issue, but impending litigation has been described in a number of studies of patients with unexplained motor symptoms and tremor.^18,²¹

Neurological Comorbidity.

In one study in the United Kingdom, 42% of patients with unexplained motor symptoms had a comorbid neurological disease and, interestingly, one half of these had a peripheral origin.¹⁸ Epilepsy is believed to coexist in a significant percentage of patients with nonepileptic seizures.²²

History from Relative/Informant.

There is a considerable amount of evidence to suggest that the observations and attitudes of caretakers may be important in the perpetuation of medically unexplained symptoms, especially motor conversion symptoms. For example, Davison and associates ²³ found caretakers to be ill informed and dissatisfied with the advice they had received from doctors about their relatives’ diagnosis and disabilities.

The Examination and Diagnostic Discrepancies

There is often a discrepancy between the patient’s concept of the symptoms and the physician’s knowledge of the anatomy and physiology. The way in which a patient moves or undresses may indicate a global affectation that is incompatible with a specific nerve lesion or with a hemiplegia.

Give-way weakness is often used as a diagnostic test of hysterical paralyses, but it is unreliable. Unilateral functional weakness of a leg, if severe, tends to produce a characteristic gait in which the leg is dragged behind the body as a single unit, like a sack of potatoes. The hip is either held in external or internal rotation so that the foot points inward or outward. The most impressive quantitative discrimination to date between hysterical and neurological weakness is reported in a study of Hoover’s sign—the involuntary extension of hysterically paralyzed leg when the “good leg” is flexing against resistance. Ziv and colleagues ²⁴ demonstrated a clear difference in the pattern of response between neurological and psychogenic patient groups. It should be borne in mind, however, that the patient may have both a functional disorder and an organic disorder.²⁵

Individual Symptoms

Paralyses

Paralyses may affect one or more limbs or one side of the face. They may be flaccid or occur with contractures. In a hysterical spasm, both arm and leg are contracted on the same side of the body, the hand is closed tightly, the knee is flexed, and perhaps the leg and the foot are drawn up. Paralysis with contractures is one of the most extreme examples of disability caused by hysterical illness.

Hysterical paraplegia has been described,²⁶ and both spinal and orthopedic surgeons, as well as rehabilitation specialists and neurologists, should be alert to the development of this disorder in their patients.²⁷ These patients have the potential to use considerable health care resources.²⁸

Abnormal Movements

Psychogenic movement disorders are believed to account for 1 per 30 patients attending a movement disorder clinic ²¹ and have been the subject of a book.²⁹ Since the mid-1980s, a number of case series of patients with psychogenic dystonia have been reported. Fahn and Williams³⁰ described 21 cases in 1988, and Lang³¹ subsequently described 18 more. Clinical features that suggest a psychogenic movement disorder are shown in Table 20-3.

TABLE 20-3 Features Suggestive of a Psychogenic Movement Disorder

Abrupt onset

Inconsistent movements (changing characteristics over time)

Incongruous movements (movements do not fit with recognized patterns or with normal physiological patterns)

Presence of additional types of abnormal movements that are not consistent with the basic abnormal movement pattern or are not congruous with a known movement disorder, particularly:

Rhythmical shaking

Bizarre gait

Deliberate slowness in carrying out the requested voluntary movement

Bursts of verbal gibberish

Excessive startle (bizarre movements in response to sudden, unexpected noise or threatening movement)

Entrainment of the psychogenic tremor to the rate of the requested rapid successive movement the patient is asked to perform

Demonstrating exhaustion and fatigue

Spontaneous remissions

Movements disappear with distraction

Response to placebo, suggestion, or psychotherapy

Presence as a paroxysmal disorder

Dystonia beginning as a fixed posture

Adapted from Fahn S: Psychogenic movement disorders. In Marsden CD, Fahn S, eds: Movement Disorders: 3. Oxford, UK: Butterworth-Heinemann, 1995, pp 359-372.

In a systematic study of 103 patients with fixed dystonia, Schrag and associates (2004)³² found that 37% fulfilled criteria for psychogenic dystonia and 29% fulfilled criteria for somatization disorder, which is characterized by chronic, multiple, persistent, medically unexplained symptoms. Although many patients fulfilled strict criteria for a somatoform disorder/psychogenic dystonia, the diagnosis remained uncertain in a proportion of patients, and whether the disorder was primarily neurological or psychiatric remains an open question. Such patients require the services of a multidisciplinary team.

Seizures (Psychogenic Nonepileptic Seizures)

It is estimated that more than 25% of patients receiving a diagnosis of refractory epilepsy in a chronic epilepsy clinic do not have epilepsy.³³ Although the population incidence of psychogenic nonepileptic seizures (PNESs) may be only 4% that of epilepsy, PNES constitutes a large share of the workload of neurologists and of emergency and general physicians. A number of details in the patient’s history may suggest a diagnosis of PNES rather than epileptic seizures (Table 20-4).

TABLE 20-4 Details in Patients’ History That May Suggest a Diagnosis of Psychogenic Nonepileptic Seizures Rather Than Epileptic Seizures

Feature in History	Psychogenic Nonepileptic Seizures	Epileptic Seizures
Manifestation at age <10 years	Unusual	Common
Change in symptoms	Occasional	Rare
Aggravation by AEDs	Occasional	Rare
Seizures in presence of physicians	Common	Unusual
Recurrent “status epilepticus”	Common	Rare
Multiple unexplained physical symptoms	Common	Rare
Multiple operations/invasive tests	Common	Rare
Psychiatric treatment	Common	Rare
Sexual and physical abuse	Common	Rare

AED, antiepileptic drug.

Adapted from Reuber M, Elger C: Psychogenic non epileptic seizures: review and update. Epilepsy Behav 2003; 4:205-216.

PNESs can be distinguished from epileptic seizures: PNESs generally occur in the presence of an audience or when another person is close by. They may be precipitated by stress but more often seem to occur in response to the social setting. The fall to the ground is not usually abrupt, and movements may follow the fall with clutching, but the characteristic regular tonic-clonic sequence of epilepsy is not found. Tongue biting and incontinence of urine are rare in hysterical seizures, the corneal reflexes are preserved, and the plantar muscles are flexed, unless previously abnormal. Firm handling and pressure on the supraorbital nerves to the point of pain may arouse the patient. PNESs occur most often among epileptic patients or among others who have seen epileptic seizures. A few epileptic patients learn how to induce ictal discharges and can produce extra seizures. Although rarely available during a seizure, the electroencephalogram is generally abnormal in epilepsy and normal during hysterical seizures.²²

It usually takes several years to arrive at the diagnosis of PNES, and 75% of patients (with no additional epilepsy) are treated with anticonvulsants initially. If PNES is not diagnosed and managed early, significant iatrogenic harm may occur. The outcome is not always favorable in these patients: in one study carried out at a mean of 11.9 years after manifestation and 4.1 years after diagnosis of PNES, 71% of patients continued to have seizures and 56% were dependent on Social Security. Outcome was better in patients with greater educational attainments, younger age at onset and diagnosis, attacks with less dramatic features, and fewer additional medically unexplained complaints.³⁴

It has been reported that patients with PNES have a consistently different psychosocial profile from patients with motor conversion symptoms. In a prospective study of consecutive neurological inpatients with either motor conversion or pseudoseizures of recent onset, patients with PNES were younger, more likely to have both an emotionally unstable personality disorder and a worse perception of parental care, more likely to report incest, and more likely to have reported more life events in the 12 months before symptom onset than were patients with motor conversion symptoms.²⁰

Sensory Symptoms

Sensory Disturbance

The clinical detection and localization of sensory dysfunction is probably one of the least reliable areas of the neurological examination. Sensory loss may involve one half of the entire body from head to toe or from right to left. It may affect the whole of a limb and characteristically has a glove or stocking distribution on the arms or legs or both. The sensory loss generally fails to fit in with known anatomical boundaries but conforms more with the patient’s concept of physiology and anatomy. Thus, hysterical sensory loss is likely to stop sharply at the midline, whereas nonhysterical sensory change only approaches the midline, inasmuch as at this point segmental nerves overlap by one or two centimeters on each side.

Unfortunately, these classic signs are often unreliable. Gould and coworkers ³⁵ found “psychogenic” features on sensory examination in more than one half of their neurological patient group, and diminished vibration sense over the affected part of the forehead was noted in 69 of 80 patients with neurological disorders.³⁶ This study also revealed that “midline splitting” of sensory function was not helpful in determining whether there was an underlying neurological disorder. These clinical findings should clearly be interpreted with circumspection.

Hemisensory disturbances can often manifest as emergencies; sometimes the patient ascribes the symptoms to “a stroke,” in association with anxiety and panic and other physical symptoms of anxiety.³⁷ These symptoms may be provoked by hyperventilation³⁸ or hypnotic suggestion.³⁹ The pathophysiological mechanisms underlying these changes are not as yet understood. Toth⁴⁰ described 34 patients with the “hemisensory syndrome,” in which patients present with hemisensory disturbance and intermittent blurring of vision in the ipsilateral eye (asthenopia) and sometimes ipisilateral hearing problems as well. Hemisensory symptoms are increasingly recognized in patients with chronic pain and in patients with reflex sympathetic dystrophy.

Visual Disturbances

Ophthalmologists have estimated that psychogenic visual disorders account for up to 5% of their practice.⁴¹ Simple observation of visually guided behavior sometimes reveals telling inconsistencies, particularly in the case of severe apparent visual loss. A number of reliable optometric techniques are available to support bedside tests and the diagnosis of psychogenic visual loss, field disturbance, or gaze abnormality (for more details, see Stone and Zeman¹⁶). Disabling hysterical blindness presents more difficulties. Evoked potential studies help demonstrate intact visual pathways.

PROGNOSIS

Outcome in published studies depends to some degree on the setting: tertiary referral centers tend to attract patients with chronic or intractable symptoms. Better outcomes appear to be associated with short or acute onset and early improvement. There is little chance of improvement once the symptoms have become chronic and enduring.⁴²

The etiological implications accruing from follow-up studies ^43,⁴⁴ are that a short history and young age are predictors of good outcome, whereas the presence of a personality disorder, chronicity of symptoms, receipt of disability benefits, and involvement with litigation predict poor recovery. Ron⁴² wrote an excellent recent review of this topic.

Patients with chronic motor symptoms (e.g., unilateral functional weakness), as well as those with sensory symptoms, appear to do particularly poorly. In particular, patients with unexplained motor symptoms who are referred to tertiary care centers continue to do very poorly after discharge. Despite the stability of the diagnosis, a pattern of multiple hospital referrals continues for many of these patients once they have been discharged from the tertiary care center. Interviews of patients conducted an average of 6 years after their original admission to a tertiary care center revealed that many continued to be referred to neurologists and other specialists but that subsequent psychiatric referral was rare.⁴³ Many changed their primary care physician after discharge from the hospital, and a disproportionate number of repeated referrals was made by primary care physicians who had known their patients for less than 6 months. Psychological attribution of symptoms was rare, and many patients felt dissatisfied with the treatment they had received. Many were exposed to unnecessary iatrogenic harm. These consistent findings of very poor outcome after discharge from neurological outpatient and inpatient services in patients with both unexplained motor disorders and PNES suggest that every neurological service should have access to referral to specialist liaison psychiatry services. Such patients are often very difficult to treat and, because of their poor prognosis, should have a reasonable chance of obtaining early and appropriate management for their primary disorder.^44,⁴⁵ Without appropriate treatment, the prognosis is poor (Table 20-5).

TABLE 20-5 Follow-up Studies (1998 to 2003) of Patients with Unexplained Motor Symptoms

MANAGEMENT

Resources

Before any discussion of treatment, it is important to consider the resources available to the neurologist to manage these patients. In contrast to disorders such as multiple sclerosis and schizophrenia, which have similar prevalences, there are no designated resources for patients with psychogenic disorders. Some neurologists may have no access whatsoever to mental health resources, whereas others may have close collaborative links with either clinical psychology or psychiatry services. There is no doubt that the successful management of these patients requires the cooperation of a number of clinical specialties, including psychologists, nurses, physiotherapists, and occupational therapists. Some patients may be so disturbed or disabled (or both) that they may require inpatient admission to a specialized unit with access to both mental health and medical nurses, as well as to physiotherapists and occupational therapists. In the opinion of this writer, every neurology service should have access to a specialist liaison psychiatry service.⁴⁶

Management Strategies for the Neurologist

First, the diagnosis has to be established by a neurologist after relevant organic disease has been ruled out. Second, the neurologist not only must explain to the patient that there is no serious underlying organic disease but also must provide an explanation for the symptoms that is comprehensible to the patient.

During the initial assessment, it is important for the neurologist to inquire about a number of psychosocial problems as part of the general interview. Key questions include the following:

1. “Have you experienced any distressing setbacks or reversals in the last 6-9 months?” (life events)

2. “How have you been feeling in your mood? Have you been feeling low; or tense or wound up; or panicky?” (anxiety and depression)

3. “What do you think is causing the symptoms? What is your worst fear?” (illness beliefs)

4. “What impact are the symptoms having on your life?” (functional impairment)

Armed with this information, the neurologist may be able to make some kind of initial formulation, such as the following:

We have completed our tests, and I am pleased to say that all results are normal, and we have not found any evidence of disease. However, I know that your symptoms are distressing, and they are certainly real. I recall your telling me that the weakness in your left leg began 9 months ago with altered sensation in your left toes. You also said that you became tense and upset at work around this time, with problems with your sleep and memory and feeling panicky in crowds. I am struck by the fact that these symptoms came on soon after your disagreement with your manager and failure to get a promotion, and life has been difficult for you since then. Have you thought about it like that?

After this, the neurologist may wish to help the patient establish mind-body links by saying something like the following:

You have what we call functional weakness: All the parts of the nervous system are there but are just not working properly, so that when you try to move your leg, it doesn’t do it as well as it should. Sometimes stress can cause these symptoms, which are often accompanied by feelings of frustration, worry, and sadness but these are not the cause of the problem. Stress is a common problem and can lead to hypertension and duodenal ulcers, as well as what we call functional weakness.

This explanation can be supplemented by giving the patient a fact sheet containing information about functional weakness, which contains information about how to become involved with rehabilitation (J. Stone, personal communication, 2006).

It is worth noting at this stage that patients prefer the term functional rather than hysterical, when their unexplained weakness, seizures, and other symptoms are being referred to.⁴⁶

The neurologist can supplement this interview by using rating scales, which provide useful baseline pretreatment information. They include the Hopkins Symptom Checklist somatization scale to measure somatic symptoms ⁴⁷; the Hospital Anxiety and Depression Scale to measure anxiety and depression⁴⁸ (the Beck Depression and Anxiety scales are also useful); and the Illness Perception Questionnaire, which provides a rating of illness attitudes and concerns.⁴⁹ There are several measures of functional impairment, including the Dartmouth Primary Care Cooperative Information Project⁵⁰ and the Barthel index.⁵¹

Referral to Psychiatrist/Psychologist

Discussing referral to a mental health specialist with the patient is a skilled process requiring the neurologist to provide a rationale for the referral without alienating the patient. Neurologists in training are not routinely taught these skills. One suggested method might be to use the following explanations:

“You have a number of physical and psychological (stress) symptoms at present.”

“The physical symptoms are real but do not reflect any underlying damage.”

“In our experience, it is as important to deal with the psychological as well as the physical symptoms in problems like this (such as functional weakness).”

“Would you like me to organize a referral to a psychiatrist/psychologist who has a specific interest in your problems?”

[If relevant] “This person works in the general hospital and has had a lot of experience dealing with patients with similar problems.”

Further Management

Traditional behavioral approaches to treatment are based on the premise that the symptoms reported by the patient are interpreted as physical but are amenable to recovery. The aim of treatment is to bring about a gradual increase in function through a combination of physical and occupational therapies. The patient receives rewards and praise for improvement of function, and reinforcement is withdrawn for continuing signs of disability. Avoiding direct confrontation of psychological problems and providing “face-saving” techniques are also regarded as key components.⁵² More recently, the approach to patients has changed from a predominantly medical one to one in which psychological and sociocultural aspects are equally important, and the need for organized specialist rehabilitation services involving a multidisciplinary team is recognized as essential.

What Is the Evidence?

With one or two exceptions,⁵³ there are no large, randomized, controlled studies of treatment in patients with conversion disorders. Nor is there any good evidence to support the use of one specific intervention, such as biofeedback, hypnosis, or psychotherapy. Although repeated case series have documented the effectiveness of multidisciplinary inpatient behavioral treatment, there is little controlled research. In an innovative approach, a “strategic behavioral intervention” was shown to be superior to standard behavioral treatment for chronic nonorganic motor disorders.⁷ In this method, patients and their families were told that full recovery constituted proof of an organic etiology, whereas failure to recover was definite proof of psychiatric etiology. This approach clearly requires special facilities and trained personnel.