A historical review of functional neurological disorder and comparison to contemporary models.

Over the centuries, various etiologies have been proposed to explain functional neurological disorders (FND), including functional seizures. These have included models relying on supernatural influences upon the body, emphasis on consequences of malfunctioning reproductive organs, the bodily expression of painful emotions involving traumatic memories, or cognitive distortions through attention and predictive biases. Many theorists, especially since the 19th century, have had overlapping themes that continue to be relevant in modern clinical use. Treatments developed in accordance with different conceptual mechanisms. Given the heterogeneity of the disorder and the variable response to individual treatments obtained through history, physicians must consider symptom expression of an FND as an overestimation. An appreciation of multiple theories allows flexible development of unique treatment plans for individual patients.