DSM-5 recast the criteria for conversion disorder, now called functional neurological symptom disorder, around a positive requirement: there must be clinical evidence of incompatibility between the symptom and recognized neurological or medical conditions. A positive Hoover sign and a sensory boundary that splits the midline and moves on retesting are exactly that evidence. The symptom must also cause clinically significant distress or impairment, which is met here.
Two earlier requirements were removed. The identification of a preceding psychological stressor is no longer required, because although meta-analysis confirms that stressful life events and childhood maltreatment, particularly emotional neglect, are substantially more common in patients than in controls, a consistent proportion of patients report no stressor at all. The stipulation that the symptom not be intentionally produced was also dropped, because feigning cannot be reliably established and the criterion asked clinicians to do the impossible. In ICD-10 the equivalent conditions sit under the dissociative (conversion) disorders as F44, with subtypes such as F44.4 for motor and F44.5 for convulsions.
Criteria-level knowledge of functional neurological symptom disorder is expected of a solid PGY-3 or PGY-4, placing this at the Intermediate level of RITE content. The practical consequence is that a neurologist can and should make this diagnosis positively at the bedside without needing a psychiatric formulation first.
Incorrect Answers
- A. A stressor would be required under DSM-IV but not DSM-5; about a third of patients have no identifiable psychological precipitant or psychiatric comorbidity.
- B. DSM-5 deliberately removed the requirement to exclude intentional production, since feigning cannot be reliably demonstrated in clinical practice.
- C. Normal investigations are supportive but not required; the diagnosis can coexist with abnormal scans and with genuine neurological disease.
- D. There is no minimum duration; DSM-5 asks only that the symptom be specified as acute if less than six months or persistent if longer.
Testing Pearls
- DSM-5 requires positive evidence of internal inconsistency or incongruity with disease.
- A psychological stressor is no longer required for the diagnosis.
- The criterion that symptoms not be feigned was removed in DSM-5.
- Emotional neglect in childhood carries a higher odds ratio than sexual or physical abuse.
- ICD-10 codes these conditions as dissociative (conversion) disorders under F44.
References
- Jankovic J, Mazziotta JC, Newman NJ, Pomeroy SL, editors. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022. p. 2077.
- Ludwig L, Pasman JA, Nicholson T, Aybek S, David AS, Tuck S, et al. Stressful life events and maltreatment in conversion (functional neurological) disorder: systematic review and meta-analysis of case-control studies. Lancet Psychiatry. 2018;5(4):307-320.
- Espay AJ, Aybek S, Carson A, Edwards MJ, Goldstein LH, Hallett M, et al. Current concepts in diagnosis and treatment of functional neurological disorders. JAMA Neurol. 2018;75(9):1132-1141.
