Prognosis of functional neurologic disorders

Abstract

The prognosis of functional (psychogenic) neurologic disorders is important in being able to help answer patients' and carers' questions, determine whether treatment is worthwhile, and to find out which factors predict outcome. We reviewed data on prognosis of functional neurologic disorders from two systematic reviews on functional motor disorders and dissociative (nonepileptic) seizures as well as additional studies on functional visual and sensory symptoms. Methodologic problems include heterogeneity in studied samples and outcome measures, diagnostic suspicion and referral bias, small size and retrospective design of available studies, possible treatments during follow-up, and literature review bias. With these caveats, the prognosis of functional neurologic disorders does appear to be generally unfavorable. In most studies, functional motor symptoms and psychogenic nonepileptic attacks remain the same or are worse in the majority of patients at follow-up. Measures of quality of life and working status were often poor at follow-up. Frequency of misdiagnosis at follow-up was as low as other neurologic and psychiatric disorders. Long duration of symptoms was the most distinct negative predictor. Early diagnosis and young age seem to predict good outcome. Emotional disorders and personality disorders were inconsistent predictors. Litigation and state benefits were found to be negative predictors in some studies, but others found they did not influence outcome.

Keywords: conversion disorder; functional neurologic disorder; misdiagnosis; natural history; prognosis; prognostic factors; psychogenic.