Neurobiologic theories of functional neurologic disorders.

Although neurobiologic theories to explain functional neurologic symptoms have a long history, a relative lack of interest in the 20th century left them far behind neurobiologic understanding of other illness. Here we review the proposals for neurobiologic mechanisms of functional neurologic symptoms that have been made over time and consider how they might inform our diagnostic and treatment methods, and how they integrate with psychologic formulations of functional symptoms. Modern approaches map on to recent developments in theoretic models of brain function, and suggest a key role for processes affecting attention, beliefs/expectations, and a resultant impairment of sense of agency.