The neuropsychology of functional neurological disorders

Figures & data

Figure 1. A simplified diagram of functional neurological disorder subtypes.

Note: The figure is not exhaustive and is meant to depict an evolving understanding of FND manifestations. Functional seizures, functional movement disorders, and functional cognitive disorder have the most empirical support for cognitive and mental health symptoms. PNES = psychogenic nonepileptic seizures.

Table 1. Further readings related to FNDs.

Topic	Readings
FND Introduction, History, Frameworks, and Cognitive Functioning	Edwards et al. (2023). Why functional neurological disorder is not feigning or malingering. Nature Reviews Neurology, 19(4), 246–256. Hallett et al. (2022). Functional neurological disorder: New subtypes and shared mechanisms. The Lancet Neurology, 21(6), 537–550. Teodoro et al. (2018). A unifying theory for cognitive abnormalities in functional neurological disorders, fibromyalgia and chronic fatigue syndrome: Systematic review. Journal of Neurology, Neurosurgery & Psychiatry, 89(12), 1308–1319.
FS Etiology, Clinical Impairment, Diagnosis, and Cognitive Functioning	Asadi-Pooya (2021). Functional seizures are not less important than epilepsy. Epilepsy & Behavior Reports, 16, 100495. Baslet et al. (2021). Evidence-Based Practice for the Clinical Assessment of Psychogenic Nonepileptic Seizures: A Report From the American Neuropsychiatric Association Committee on Research. The Journal of Neuropsychiatry and Clinical Neurosciences, 33(1), 27–42. Ertan et al. (2022). Functional (psychogenic non-epileptic/dissociative) seizures: Why and how? Journal of Neurology, Neurosurgery & Psychiatry, 93(2), 144–157.
FCD Identification, Differential Diagnosis, and Clinical Characterization	Ball, H. A., Swirski, M., Newson, M., Coulthard, E. J., & Pennington, C. M (Perez, Aybek, et al., 2021). Differentiating Functional Cognitive Disorder from Early Neurodegeneration: A Clinic-Based Study. Brain Sciences, 11(6), 2895–2903. Cabreira, Frostholm, et al. (2023). Clinical signs in functional cognitive disorders: A systematic review and diagnostic meta-analysis. Journal of Psychosomatic Research, 173, 111447. McWhirter et al. (2020). Functional cognitive disorders: A systematic review. The Lancet Psychiatry, 7(2), 191–207.
FMD Clinical Characterization and Cognitive Functioning	Alluri et al. (2020). Cognitive Complaints in Motor Functional Neurological (Conversion) Disorders: A Focused Review and Clinical Perspective. Cognitive and Behavioral Neurology, 33(2), 77–89. (On behalf of the American Neuropsychiatric Association Committee for Research, Perez, Aybek, et al. (2021). Decade of progress in motor functional neurological disorder: continuing the momentum. Journal of Neurology, Neurosurgery & Psychiatry, 92, 668–677. Věchetová, et al. (2018). The impact of non-motor symptoms on the health-related quality of life in patients with functional movement disorders. Journal of Psychosomatic Research, 115, 32–37.

The recommended reading list is selective, introductory, and nonexhaustive. FCD = functional cognitive disorder; FMD = functional movement disorder; FND = functional neurological disorder; FS = functional seizure.

Edwards, M. J., Yogarajah, M., & Stone, J. (2023). Why functional neurological disorder is not feigning or malingering. Nature Reviews Neurology, 19(4), 246–256. https://doi.org/10.1038/s41582-022-00765-z

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Hallett, M., Aybek, S., Dworetzky, B. A., McWhirter, L., Staab, J. P., & Stone, J. (2022). Functional neurological disorder: New subtypes and shared mechanisms. The Lancet Neurology, 21(6), 537–550. https://doi.org/10.1016/S1474-4422(21)00422-1

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Teodoro, T., Edwards, M. J., & Isaacs, J. D. (2018). A unifying theory for cognitive abnormalities in functional neurological disorders, fibromyalgia and chronic fatigue syndrome: Systematic review. Journal of Neurology, Neurosurgery & Psychiatry, 89(12), 1308–1319. https://doi.org/10.1136/jnnp-2017-317823

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Asadi-Pooya, A. A. (2021). Incidence and prevalence of psychogenic nonepileptic seizures (functional seizures): A systematic review and an analytical study. International Journal of Neuroscience, 133(6), 598–603. https://doi.org/10.1080/00207454.2021.1942870

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Baslet, G., Bajestan, S. N., Aybek, S., Modirrousta, M., Price, J., Cavanna, A., Perez, D. L., Lazarow, S. S., Raynor, G., Voon, V., Ducharme, S., & LaFrance, W. C. (2021). Evidence-based practice for the clinical assessment of psychogenic nonepileptic seizures: A report from the American neuropsychiatric association committee on research. The Journal of Neuropsychiatry and Clinical Neurosciences, 33(1), 27–42. https://doi.org/10.1176/appi.neuropsych.19120354

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Ertan, D., Aybek, S., LaFrance, W. C., Jr., Kanemoto, K., Tarrada, A., Maillard, L., El-Hage, W., & Hingray, C. (2022). Functional (psychogenic non-epileptic/dissociative) seizures: Why and how? Journal of Neurology, Neurosurgery & Psychiatry, 93(2), 144–157. https://doi.org/10.1136/jnnp-2021-326708

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Perez, D. L., Aybek, S., Popkirov, S., Kozlowska, K., Stephen, C. D., Anderson, J., Shura, R., Ducharme, S., Carson, A., Hallett, M., Nicholson, T. R., Stone, J., LaFrance, W. C., Voon, V., & (On behalf of the American Neuropsychiatric Association Committee for Research). (2021). A review and expert opinion on the neuropsychiatric assessment of motor functional neurological disorders. The Journal of Neuropsychiatry and Clinical Neurosciences, 33(1), 14–26.

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Cabreira, V., Frostholm, L., McWhirter, L., Stone, J., & Carson, A. (2023). Clinical signs in functional cognitive disorders: A systematic review and diagnostic meta-analysis. Journal of Psychosomatic Research, 173, 111447. https://doi.org/10.1016/j.jpsychores.2023.111447

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McWhirter, L., Ritchie, C., Stone, J., & Carson, A. (2020). Functional cognitive disorders: A systematic review. The Lancet Psychiatry, 7(2), 191–207. https://doi.org/10.1016/S2215-0366(19)30405-5

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Alluri, P. R., Solit, J., Leveroni, C. L., Goldberg, K., Vehar, J. V., Pollak, L. E., Colvin, M. K., & Perez, D. L. (2020). Cognitive complaints in motor functional neurological (conversion) disorders: A focused review and clinical perspective. Cognitive and Behavioral Neurology, 33(2), 77–89. https://doi.org/10.1097/WNN.0000000000000218

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Věchetová, G., Slovak, M., Kemlink, D., Hanzlikova, Z., Dusek, P., Nikolai, T., Ruzicka, E., Edwards, M. J., & Serranova, T. (2018). The impact of non-motor symptoms on the health-related quality of life in patients with functional movement disorders. Journal of Psychosomatic Research, 115, 32–37. https://doi.org/10.1016/j.jpsychores.2018.10.001

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