Organic syndromes diagnosed as conversion disorder: identification and frequency in a study of 85 patients

https://doi.org/10.1016/S0022-3999(99)00107-5Get rights and content

Abstract

Background: The percentage of patients initially diagnosed with a conversion disorder and later identified as having an organic disorder has been decreasing in recent studies. Method: Consecutive patients with a diagnosis of conversion disorder were referred for psychiatric diagnosis and treatment. Research questions were: (1) What incidence of neurological disorder is revealed by neurological reassessment and by which diagnostic technique is the final diagnosis established? (2) What differences can be observed between true-positive and the false-positive results? Results: Ten (11.8%) of the 85 patients examined appeared to suffer from a neurological disorder. In this sample, variables discriminating between the true positives and false positives were: (1) prior suspicion of neurological disorder; (2) older age at referral; (3) older age at onset of symptoms; (4) longer duration of symptoms; and (5) use of medication. Three variables contributed significantly to the prediction of organic disorder: prior suspicion of neurological disorder; age at onset of symptoms; and duration of symptoms. Conclusions: Although our results are in line with those of other recent studies, the percentage of false positives was still high. The data further emphasize the dangers of making a diagnosis of conversion disorder in the absence of positive evidence. It is important to continue to provide follow up for patients with a diagnosis of conversion disorder. Unfortunately, unreliable psychiatric indications, like certain behavioral characteristics, are still used in the diagnostic process. The results show that a general neurological examination is still a valuable diagnostic instrument in addition to modern diagnostic techniques.

Introduction

The percentage of patients initially diagnosed with a conversion disorder [1] and later identified as having an organic disorder, in most cases a neurological disorder (i.e., a so-called false positive), has changed from the early days of Slater and Glithero [18], who considered the incidence to be high, to rather lower levels in more recent studies. Table 1 provides an overview of the most relevant studies.

Comparison of these studies is difficult for a number of reasons. First, some studies that find a high percentage of organic disorder, are quite dated. Since these works, major developments have occurred in the technical diagnosis of patients and advanced diagnostic techniques have become available 2, 3, 4, 5, 6. The studies are also difficult to compare due to differences in descriptions of the symptoms and delineation of the relevant symptom patterns (both pseudoneurological symptoms and pain symptoms or vomiting are mentioned). The fact that the diagnostic categories are often not mutually exclusive further complicates comparison 7, 8. In such a manner, Weintraub [9] cited a high false-positive rate of 63.5% in a study by Whitlock [10], but his patient group consisted of patients with coexisting neurological or organic disease.

Considerable differences between these studies also exist in the duration of the symptoms, the frequency of repeated physical examination, the thoroughness and care with which the diagnosis was performed, the research setting, and the time of follow-up. It appears that, with increased follow-up time, there is an increased probability of encountering neurological disease that can, in retrospect, explain the initial symptoms.

Finally, in a number of studies, diagnoses were determined by exclusion of an organic disease without further positive confirmation on the basis of psychiatric examination. In contrast, there are indications that patients with a previous psychiatric history are at a greater risk of having their neurological symptoms attributed to a psychiatric syndrome [5].

The aim of the present study was to explore the following questions:

  • 1.

    What incidence of neurological disorder is revealed by neurological reassessment, and by which diagnostic technique is the final diagnosis established?

  • 2.

    What differences can be observed between the organic or false-positive group and the conversion or true-positive group on the basis of the available information?

Section snippets

Method

Neurological reassessments and psychiatric examinations were undertaken on consecutive patients with a prior diagnosis of conversion disorder upon their referral to a Dutch psychiatric hospital (De Grote Rivieren) for examination and treatment during 1991 to 1996 11, 12, 13.

Inclusion criteria for the study were:

  • A diagnosis of motor-type conversion disorder (i.e., paresis or paralysis, gait disturbances, coordination problems, abasia–astasia, aphonia, fits or pseudoepileptic seizures with motor

Subject characteristics

Our sample consisted of 85 patients (21.2% men and 78.8% women). Upon referral, their mean age was 38 years (sd = 12.7, range 17 to 65) with a mean onset at the age of 33.5 years (sd = 12.6; range 15 to 67). The duration of the symptoms was an average of 4.3 years (sd = 6.0, median 3.8 years, range 2 months to 34 years). In 27 (32.1%) patients, the onset of the symptoms had been acute (within 1 week). Forty (47.6%) patients had reported the same or other conversion symptoms in the past.

Discussion

In this study, we found that 11.8% of the sample consisted of false-positive conversion disorder patients. Compared with the conversion group, the organic group needed a surplus of supplemental examinations before the final diagnosis could be made. Comparison of both groups revealed that they differed significantly with respect to prior suspicion of neurological disorder, age at onset of symptoms, duration of symptoms, age at referral, and use of medication. The first three of these five

References (25)

  • S.L. Snyder

    Commentarycontra pseudoseizure. The problem of intention in nonepileptic events

    Gen Hosp Psychiatry

    (1994)
  • E. Slater et al.

    A follow-up of patients diagnosed as suffering from hysteria

    J Psychosom Res

    (1965)
  • Diagnostic and statistical manual of mental disorders

    (1995)
  • C. Spierings et al.

    Conversion disorders in childhooda retrospective follow-up study of 84 inpatients

    Devel Med Child Neurol

    (1990)
  • W. Couprie et al.

    Outcome in conversion disordera follow-up study

    J Neurol Neurosurg Psychiatry

    (1995)
  • C.J. Mace et al.

    Ten-year prognosis of conversion disorder

    Br J Psychiatry

    (1996)
  • H.L. Crimlisk et al.

    Slater revisited6 year follow-up study of patients with medically unexplained motor symptoms

    BMJ

    (1998)
  • H. Merksey et al.

    Hysteria and organic brain disease

    Br J Med Psychol

    (1975)
  • F.P. McKegney

    The incidence and characteristics of patients with conversion reactionsI. A general hospital consultation service sample

    Am J Psychiatry

    (1967)
  • M.I. Weintraub

    Hysterical conversion reactionsa clinical guide to diagnosis and treatment

    (1983)
  • F.A. Whitlock

    The aetiology of hysteria

    Acta Psychiatrica Scand

    (1967)
  • F.C. Moene et al.

    The inpatient treatment of patients suffering from (motor) conversion symptomsa description of eight cases

    Int J Clin Exper Hypnos

    (1998)
  • Cited by (33)

    • Positive clinical signs in neurological diseases – An observational study

      2019, Journal of Clinical Neuroscience
      Citation Excerpt :

      On certain occasions, patients with organic disorders have been misdiagnosed as functional neurological disorders and vice versa [4,5]. While earlier studies have erroneously diagnosed organic syndromes as conversion disorder in 4–60% of patients, recent advances in practice and diagnostic evaluation have lowered the reported percentage to 1% [3,6]. There is a growing recognition of patients presenting with symptoms, that aren’t fully explained by the underlying organic disease [3].

    • Is physical disease missed in patients with medically unexplained symptomsα A long-term follow-up of 120 patients diagnosed with bodily distress syndrome

      2014, General Hospital Psychiatry
      Citation Excerpt :

      The patients reassessed by Moene et al. were initially diagnosed with conversion disorder at general hospitals, research hospitals or specialist epilepsy centers; hence, both patients and the diagnosing physicians were more heterogeneous than in our study. Generally, the small sample sizes in most of the comparable studies [14–20,22] are subject for statistical inaccuracy, which becomes apparent in the overlapping CIs (Table 1). When compared to the somatoform disorder category in ICD-10 and the recently introduced somatic symptom disorder category in The Diagnostic and Statistical Manual of Mental Disorders (DSM), 5th edition [16,38,39], it is noteworthy that the BDS diagnosis does not depend on behavioral or cognitive features.

    • Somatoform Disorders

      2010, Encyclopedia of Movement Disorders, Three-Volume Set
    • Somatoform Disorders

      2010, Encyclopedia of Movement Disorders
    • Motor conversion symptoms and pseudoseizures: A comparison of clinical characteristics

      2004, Psychosomatics
      Citation Excerpt :

      In this study, there was a high frequency of pain in both groups but a much smaller overlap between pseudoseizures and motor conversion symptoms. This has been previously reported.7,13–15,44,45 Studies that have found a large overlap in background factors between somatoform pain disorder and conversion disorder46 echo the increasing realization that rather than forming separate and distinct categories, functional somatic symptoms consistently overlap.47–49

    View all citing articles on Scopus
    View full text