Several converging lines of evidence argue against feigning as a general explanation. Symptoms persist when patients are unobserved and during sleep-related and covert monitoring; most patients do not obtain financial benefit and many lose income; symptoms commonly continue unchanged after compensation claims are settled; patients accept unpleasant and invasive investigations and treatments; the disorder is often long lasting and disabling in ways that would be extraordinarily difficult to maintain deliberately; and reproducible physiologic and functional imaging correlates have been demonstrated, including the Bereitschaftspotential in functional myoclonus and altered activity in agency-related cortical networks.
The features the colleague cites as evidence of feigning are in fact predicted by the mechanistic model. Fluctuation, distractibility and reversibility by suggestion follow directly from a disorder of attention and of the sense of agency in which the movement is generated by voluntary circuitry but not experienced as voluntary. That is why the same signs that reveal the diagnosis, such as Hoover sign, entrainment and the readiness potential, cannot be used to infer deception; they demonstrate an intact motor system, not a deceiving mind. Malingering does exist, but it is uncommon in clinical practice and requires independent evidence of deliberate deception for external reward.
On the ABPN blueprint this maps to the Neuroscience and mechanism of disease axis, because the argument turns on the pathophysiologic model of the disorder. Communicating this coherently to colleagues and to patients is a core professional skill in this field.
Incorrect Answers
- A. Self-report alone is not evidence, since a person who was feigning would make the same claim; the argument requires external corroboration.
- C. Adversity and stressors are more common than in controls but a substantial proportion of patients report none, so they cannot explain the disorder.
- D. Duration is not proof of authenticity; factitious disorder can be sustained for years.
- E. Normal imaging and routine electrophysiology are equally compatible with feigned symptoms and therefore carry no discriminative weight.
Testing Pearls
- Symptoms persist unobserved and after litigation settles, arguing against feigning.
- Most patients gain no financial benefit and accept unpleasant investigation and treatment.
- Reproducible physiologic correlates such as the Bereitschaftspotential support a genuine disorder.
- Distractibility and reversibility are predicted by the attention and agency model.
- Malingering is uncommon and requires independent evidence of deception for external reward.
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. 2087.
- 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.
- Bass C, Halligan P. Factitious disorders and malingering: challenges for clinical assessment and management. Lancet. 2014;383(9926):1422-1432.
