Conversion syndromes in neurology. A psychopathological and psychodynamic differentiation of conversion disorder, somatization disorder and factitious disorder

Conversion syndromes are frequent among medically unexplained somatic symptoms in neurology. A careful differential diagnosis must be carried out in a psychiatric consultation service. In a prospective study lasting for over four years 169 patients with pseudoneurological signs of conversion were included. From a clinical point of view the following conversion syndromes were presented: astasia/abasia: 27.2%, paresis/plegia: 24.3%, aphonia: 1.8%, hyp-/anaesthesia: 21.9%, blindness: 5.3%, non-epileptic seizures: 19.5%. According to the diagnostic criteria of DSM-III-R three subgroups were differentiated: conversion disorder (n = 132), somatisation disorder (n = 28), factitious disorder (n = 9). Intermittent courses of illness were prevailing in conversion disorder, whereas chronic courses predominated in the other two subgroups. High rates of psychiatric comorbidity were typical signs of somatisation disorder. Frequent autodestructive motives (suicidality, deliberate and covert self-harm, chronic pain, high rate of operations) in illness behaviour had to be registered in somatisation and factitious disorder. Both subgroups were characterised by frequent traumatic events during early development. Important socio-economic aspects of illness behaviour above all in somatisation and factitious disorder were underlined. The results are discussed in terms of psychiatric differential diagnosis and psychiatric comorbidity, psychodynamic evaluation, illness behaviour and therapeutic options in a C/L-service.