conversion disorder

**Definition (DSM-5):** Functional neurological symptom disorder (conversion disorder) involves ≥1 symptom of altered voluntary motor or sensory function. Clinical findings show incompatibility between the symptom and recognized neurological or medical conditions. The symptom is not better explained by another medical or mental disorder, and it causes clinically significant distress or functional impairment. A preceding psychological stressor is common but is NOT required for diagnosis in DSM-5.

**Common presentations:** - Motor: paralysis/weakness, abnormal movements (tremor, dystonia), gait disturbance, aphonia, difficulty swallowing ("globus"), urinary retention - Sensory: blindness, anesthesia, deafness, paresthesias, often in non-anatomic distributions (e.g., "glove-and-stocking" loss not following dermatomes) - Seizure-like episodes: psychogenic non-epileptic seizures (PNES)—often with eyes closed, prolonged duration (>2 min), side-to-side head movement, pelvic thrusting, no post-ictal confusion, normal prolactin/lactate, normal EEG during the event - Mixed

**Pathophysiology:** Not fully understood. Proposed mechanisms include psychodynamic theory (Freud: unconscious psychological conflict "converted" into physical symptoms, producing *primary gain*—keeping the conflict out of awareness—and *secondary gain*—external benefits such as attention or avoiding responsibilities), plus functional imaging showing altered limbic–motor network connectivity and abnormal attention/self-agency processing.

**Epidemiology / risk factors:** More common in women, young adults (onset often late adolescence–early adulthood), lower socioeconomic status, rural populations. Associated with prior trauma/abuse, comorbid depression/anxiety, personality disorders, and other medical/neurologic illness.

**Exam clues:** - Symptoms inconsistent with anatomy/physiology and with a normal workup - Positive signs of internal inconsistency: Hoover sign (weakness of hip extension that resolves with contralateral hip flexion against resistance), drift without pronation, give-way weakness, tremor entrainment, astasia-abasia (dramatic, wildly swaying gait without falling) - "La belle indifférence" (inappropriate lack of concern) — classically cited but NOT specific or reliable; also seen in patients with true organic disease - Patient is unaware of the psychological origin and is not consciously faking

**Differential (frequently tested):** - *Malingering*: intentional symptom production for external gain (e.g., money, avoiding jail/military duty) - *Factitious disorder*: intentional production for the sick role/primary gain (internal gain) - *Somatic symptom disorder*: excessive thoughts/feelings/behaviors about ≥1 somatic symptoms (pain is common); symptoms are real and not limited to neurologic deficits - *Illness anxiety disorder*: preoccupation with having a serious illness despite minimal or no symptoms - Must exclude true neurologic disease (MS, stroke, myasthenia gravis, Guillain-Barré, epilepsy) and other causes (e.g., tumors, toxins)

**Management:** - Rule out organic causes with an appropriate workup, then make a *positive* diagnosis based on clinical signs - Explain the diagnosis clearly, non-judgmentally, and reassure the patient that symptoms are real and often reversible - Avoid unnecessary repeated testing or invasive procedures - Physical/occupational therapy for motor symptoms; CBT and psychotherapy (especially for PNES); treat comorbid depression/anxiety (SSRIs) - Prognosis: acute onset with a clear stressor and a short duration before diagnosis predicts a good outcome. Most symptoms resolve within days to weeks, but chronic or recurrent courses can occur.

**High-yield pearls:** - Symptoms are involuntary and unconscious; if consciously produced → malingering or factitious disorder - Primary gain = reduction of anxiety/conflict; secondary gain = external benefit - Sensory/motor deficits do not follow anatomic distributions and are not accompanied by objective findings (normal reflexes, no atrophy, no fasciculations, normal EMG/MRI) - Classic vignette: A young woman suddenly becomes blind or paralyzed after witnessing a traumatic event or a major conflict, with a normal neurologic exam, intact pupillary light reflex and normal visual evoked potentials/optokinetic nystagmus.