29B. Conversion disorders

Conversion disorder, also called functional neurological symptom disorder, refers to when a patient has neurological symptoms which cannot be fully explained by an organic neurological condition. The name comes from the theory that the patient subconsciously “converts” psychological distress neurological symptoms.

Symptoms are involuntary responses to internal or external triggers, and so they are not under conscious control (in which case it would be malingering or facticious disorder). Classically, conversion disorder has been associated with psychological factors, but such factors are not always present.

Clinical features

Virtually any neurological symptom can occur, but some are more common and characteristic than others:

Paresis/plaegia
Headache
Vertigo
Sensory loss
Seizures (see topic 11A)

There are some clinical features which suggest function disorder rather than organic neurological disorder:

They follow non-anatomical distribution
- Hemiparesis which affects the face as well
- Hemisensory loss which follows the midline, including half of the trunk
They are inconsistent and non-reproducible
They change when the patient is distracted
The tremor changes when the patient performs another motion with the other hand (entrainment test)
During pronator drift test, the arms drift downward but don’t pronate
The patient can initially provide resistance against the examiner’s force, but then suddenly “gives way” (giveaway weakness)
Hoover sign – the examiner holds both the patient’s heels and asks them to lift the weak leg. If there is no downward force on the healthy leg, the test is positive
- In normal cases and with organic weakness, flexion of one hip will trigger extension of the contralateral hip (crossed extensor reflex)

La belle indifference may be present. The patient is unbothered and calm when describing their neurological symptoms, even if they are severe. This may be because conversion symptoms “relieve” the mind of some underlying anxiety or psychiatric problem.

Diagnosis and evaluation

Conversion disorder used to be a diagnosis of exclusion, but not anymore. The diagnosis is made when physical examination shows clinical findings which are incompatible with disease or are inconsistent across different parts of the examination.

Many patients have concomitant organic neurological disorder and psychiatric disorder, and so the presence of psychiatric disorder should not by itself be an indication of conversion disorder. A patient can have both conversion disorder and organic neurological disorder.

Treatment

It’s important to inform the patient of the diagnosis properly and with respect, as education about the diagnosis sometimes improves it. Delivering the diagnosis in a suboptimal manner often leads to the patient feeling dismissed or offended, although this cannot always be prevented. As with other functional disorders, patients often get the impression that their providers think they’re making up these symptoms, intentionally faking them, or that “it’s all in their head”, and so it’s important to make sure that one understands that their symptoms are real and taken seriously. Many patients are hesitant to accept the diagnosis, insisting that there is underlying organic disease.

Here are some potentially helpful resources:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6372294/
https://pubmed.ncbi.nlm.nih.gov/30878972/
https://www.neurosymptoms.org/en_GB/
https://sites.google.com/sheffield.ac.uk/non-epileptic-attacks/
https://www.youtube.com/watch?v=4jVNVU0FuxQ

Unfortunately, there aren’t many treatment options for conversion disorders. Cognitive behavioural therapy and/or antidepressants may have some effect, but the evidence is not strong. In case of motor symptoms, physiotherapy may be useful.