Functional neurological symptom disorder, previously known as conversion disorder, consists of neurologic symptoms or deficits that develop unconsciously and nonvolitionally and usually involve motor or sensory function. The manifestations are incompatible with known pathophysiologic mechanisms or anatomic pathways. Onset, exacerbation, or maintenance of conversion symptoms is commonly attributed to psychiatric factors, such as stress or trauma. Diagnosis is based on history after excluding physical disorders as the cause. Treatment begins by establishing a consistent, supportive physician-patient relationship; psychotherapy can help, as may hypnosis and physical therapy.
Functional neurological symptom disorder is a form of somatization—the expression of psychiatric phenomena as physical (somatic) symptoms.
The disorder tends to develop during late childhood to early adulthood but may occur at any age. There is a marked female preponderance of 60 to 80%, although the gender gap narrows at extremes of age (1).
General reference
1. Hallett M, Aybek S, Dworetzky BA, McWhirter L, Staab JP, Stone J. Functional neurological disorder: new subtypes and shared mechanisms. Lancet Neurol. 2022;21(6):537-550. doi:10.1016/S1474-4422(21)00422-1
Symptoms and Signs of Functional Neurological Symptom Disorder
Symptoms of this disorder often develop abruptly, and onset can sometimes follow a stressful event. Typically, symptoms involve apparent deficits in voluntary motor or sensory function but sometimes include shaking movements and impaired consciousness (suggesting seizures) and abnormal limb posturing (suggesting another neurologic or general physical disorder). For example, patients may present with impaired coordination or balance, weakness, paralysis of an arm or a leg, loss of sensation in a body part, seizures, unresponsiveness, blindness, double vision, deafness, aphonia, difficulty swallowing, sensation of a lump in the throat, or urinary retention.
Patients may have a single episode or sporadic repeated ones; symptoms may become chronic. Episodes are typically brief.
Diagnosis of Functional Neurological Symptom Disorder
Psychiatric assessment
General medical evaluation to exclude other etiologies
The diagnosis of functional neurological symptom disorder is considered only after a comprehensive medical examination and testing to exclude neurologic or general medical conditions that can fully account for the symptoms and their effects. An important characteristic is that the symptoms are not consistently present and signs are not consistently reproducible with neurologic disease. For example, according to the DSM-5-TR, the symptoms may not follow anatomic distributions (eg, sensory deficits that involve parts of multiple nerve roots), or produce variable findings upon reexamination or reassessment in different ways, as in the following (1):
A patient may have marked weakness of plantar flexion when tested in bed but can walk normally on tiptoes.
In a supine patient, the examiner's hand under the heel of a "paralyzed" leg detects downward pressure when the patient lifts the unaffected leg against resistance (Hoover sign).
Tremor changes or disappears when the patient is distracted (eg, by having the patient copy a rhythmic movement with the unaffected hand).
Resistance to eye opening is detected during an apparent seizure.
A visual field deficit is tubular (tunnel vision).
To meet criteria for being functional neurological symptom disorder, the symptoms must be severe enough to cause significant distress or impair social, occupational, or other important areas of functioning.
Diagnosis reference
1. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 5th ed, Text Revision. American Psychiatric Association Publishing; 2022.
Treatment of Functional Neurological Symptom Disorder
Supportive, trustful relationship with clinician
Sometimes hypnosis or cognitive-behavioral therapy
The treatment of functional neurological symptom disorder involves a multimodal approach that frequently requires collaboration between neurologists, psychiatrists, primary care clinicians, and allied health professionals (eg, physical therapists). The therapeutic process must incorporate a consistently trustful and supportive physician-patient relationship.
The diagnostic explanation (ie, discussion of the diagnosis as a legitimate psychiatric disorder and its implications) is a critical therapeutic intervention that should validate the patient's symptoms as genuine, establish confidence in the diagnosis based on positive findings, foster a partnership with the clinician, and provide a clear rationale for multidisciplinary management (1).
The following treatments may help:
Psychotherapy, including cognitive-behavioral therapy, is effective for some people.
Physical therapy can help some people.
Hypnotherapy is a complementary, short-term therapy that may help by enabling patients to control the effects of stress and their mental state on their bodily functions.
There is currently no evidence supporting the use of pharmacotherapy for functional neurological symptom disorder in patients without a psychiatric comorbidity. However, if present, associated psychiatric disorders (eg, depression, anxiety, posttraumatic stress disorder) should be treated, and treatment approaches for such disorders may involve the use of pharmacotherapy.
Treatment reference
1. Espay AJ, Aybek S, Carson A, et al. Current Concepts in Diagnosis and Treatment of Functional Neurological Disorders. JAMA Neurol. 2018;75(9):1132-1141. doi:10.1001/jamaneurol.2018.1264
