Functional Neurological Symptom Disorder (Conversion Disorder)

Functional Neurological Symptom Disorder, also known as Conversion Disorder, is a type of somatic disorder that is sometimes applied to patients who present with neurological symptoms, such as numbness, blindness, paralysis, or fits, which are not consistent with a well-established organic cause. The symptoms cause significant distress and can be traced back to a psychological trigger. It is thought that these symptoms arise in response to stressful situations affecting a patient’s mental health or an ongoing mental health condition such as depression.

Figure 1. Functional neurological symptom disorder (conversion disorder) occurs when physical symptoms result from psychological triggers.

Functional neurological symptom disorder (conversion disorder) begins with some stressor, trauma, or psychological distress. Usually, the physical symptoms of the syndrome affect the senses or movement. Common symptoms of functional neurological symptom disorder (conversion disorder) include blindness, partial or total paralysis, inability to speak, deafness, numbness, difficulty swallowing, incontinence, balance problems, seizures, tremors, and difficulty walking. These symptoms are attributed to functional neurological symptom disorder when a medical explanation for the afflictions cannot be found. Symptoms of functional neurological symptom disorder usually occur suddenly. Functional neurological symptom disorder (conversion disorder) is typically seen in individuals aged 10 to 35 and affects between 0.011% and 0.5% of the general population.

Functional neurological symptom disorder (conversion disorder) can present with motor or sensory symptoms including any of the following:

• motor symptoms or deficits:
  • impaired coordination or balance
  • weakness/paralysis of a limb or the entire body (hysterical paralysis or motor conversion disorders)
  • impairment or loss of speech (hysterical aphonia)
  • difficulty swallowing (dysphagia) or a sensation of a lump in the throat
  • urinary retention
  • psychogenic non-epileptic seizures or convulsions
  • persistent dystonia
  • tremor, myoclonus or other movement disorders
  • gait problems (astasia-abasia)
  • loss of consciousness (fainting)
• sensory symptoms or deficits:
  • impaired vision (hysterical blindness), double vision
  • impaired hearing (deafness)
  • loss or disturbance of touch or pain sensation

Factitious Disorder

A factitious disorder (FD) is a condition in which a person, without a malingering motive, acts as if they have an illness by deliberately producing, feigning, or exaggerating symptoms purely to attain (for themselves or for another) a patient’s role. Individuals with a factitious disorder may produce symptoms by contaminating urine samples, taking hallucinogens, injecting fecal material to produce abscesses, and similar behavior.

Factitious disorder imposed on self (also called Munchausen syndrome) was for some time the umbrella term for all such disorders. Factitious disorder imposed on another (also called Munchausen syndrome by proxy, Munchausen by proxy, or factitious disorder by proxy) is a condition in which a person deliberately produces, feigns, or exaggerates the symptoms of someone in their care. In either case, the perpetrator’s motive is to perpetrate factitious disorders, either as a patient or by proxy as a caregiver, in order to attain (for themselves or for another) a patient’s role. Malingering differs fundamentally from factitious disorders in that the malingerer simulates illness intending to obtain a material benefit or avoid an obligation or responsibility. Somatic symptom disorders, though also diagnoses of exclusion, are characterized by physical complaints that are not produced intentionally.