History and Pathophysiology of Functional Neurological Disorders*

Thanks to Freud’s seminal insight we know that the idea of the body, not known neurological pathways, is the basis for functional neurological disorders (FND). Whereas Freud proposed that the functional impairment in these disorders had symbolic significance, this commentary focuses on three main ideas that are consistent with Freud’s insight but explain the mechanism of FNDs somewhat differently: (1) FNDs may arise from a deficit or failure in mental representation of emotion as opposed to defenses such as repression; (2) rather than having symbolic significance, bodily symptoms and signs often lack it, consistent with a failure in mental representation; (3) rather than the primary source of distress being an unmet need creating a deviation from a homeostatic set point that is resolved in a bottom-up manner, a complementary perspective is that bodily symptoms arise due to allostasis, a prediction of what is needed in the moment in interaction with the environment, that gets transmitted to the body in a top-down manner. These proposed mechanisms have implications for clinical interventions that could be of benefit to some patients.