conversion disorders (non-specific)

Last reviewed 01/2018

Conversion disorder, also called functional neurological symptom disorder, and previously known as hysteria

• a psychiatric illness in which symptoms and signs affecting voluntary motor or sensory function cannot be explained by a neurological or general medical condition
• psychological factors, such as conflicts or stress, are judged to be associated with the deficits

Sigmund Freud first used the phrase conversion disorder

• hypothesized that the occurrence of certain symptoms not explained by organic diseases reflect unconscious conflict
• conversion refers to the substitution of a somatic symptom for a repressed idea

Examples of conversion symptoms include:

• blindness
• paralysis
• dystonia
• psychogenic nonepileptic seizures
• anaesthesia
• swallowing difficulties
• motor tics
• difficulty walking

Patients diagnosed with conversion disorder are not feigning the signs and symptoms. Despite the lack of a definitive organic diagnosis, the patient’s distress is very real and the physical symptoms the patient is experiencing cannot be controlled at will (i.e., the patient is not malingering an illness)

Unfortunately DSM-V and ICD-10 use the terms conversion and dissociation differently.

In DSM-5, the diagnostic criteria for conversion disorder (now also named functional neurologic symptom disorder) have abandoned a requirement for recent psychological stress in recognition that this is not identifiable in many patients. Instead, there is a criterion demanding evidence of the positive clinical examination features that neurologists use to make these (and other) diagnoses.

The ICD-10 classifies conversion disorder as dissociative (conversion) disorder, which suggests the symptoms arise through the process of dissociation.

According to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), conversion disorder is characterized by the following:

• one or more symptoms of altered voluntary motor or sensory function
  
  
• clinical findings that show evidence of incompatibility between the symptoms and recognized neurological or medical conditions
  
  
• symptoms or deficit that are not better explained by another medical or mental disorder
  
  
• symptoms or deficit that cause clinically significant distress or impairment in social, occupational, or other important areas of functioning or warrants medical evaluation

According to psychodynamic theory, conversion symptoms develop to defend against unacceptable impulses

• primary gain, that is to say the purpose of a conversion symptom is to bind anxiety and keep a conflict internal
  • for example
    • leg paralysis after an equestrian competitor is thrown from his or her horse. The symptom has a symbolic value that is a representation and partial solution of a deep-seated psychological conflict: to avoid running away like a coward, and yet to avoid being thrown again

According to learning theory, conversion disorder symptoms are a learned maladaptive response to stress. Patients achieve secondary gain by avoiding activities that are particularly offensive to them, thereby gaining support from family and friends, which otherwise may not be offered.