Abstract
BACKGROUND AND OBJECTIVES: Functional neurologic disorder (FND) represents genuine involuntary neurologic symptoms and signs including seizures, weakness, and sensory disturbance, which have characteristic clinical features, and represent a problem of voluntary control and perception despite normal basic structure of the nervous system. The historical view of FND as a diagnosis of exclusion can lead to unnecessary health care resource utilization and high direct and indirect economic costs. A systematic review was performed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to assess these economic costs and to assess for any cost-effective treatments. METHODS: We searched electronic databases (PubMed, PsycInfo, MEDLINE, EMBASE, and the National Health Service Economic Evaluations Database of the University of York) for original, primary research publications between inception of the databases and April 8, 2022. A hand search of conference abstracts was also conducted. Key search terms included "functional neurologic disorder," "conversion disorder," and "functional seizures." Reviews, case reports, case series, and qualitative studies were excluded. We performed a descriptive and qualitative thematic analysis of the resulting studies. RESULTS: The search resulted in a total of 3,244 studies. Sixteen studies were included after screening and exclusion of duplicates. These included the following: cost-of-illness (COI) studies that were conducted alongside cohort studies without intervention and those that included a comparator group, for example, another neurologic disorder (n = 4); COI studies that were conducted alongside cohort studies without intervention and those that did not include a comparator group (n = 4); economic evaluations of interventions that were either pre-post cohort studies (n = 6) or randomized controlled trials (n = 2). Of these, 5 studies assessed active interventions, and 3 studies assessed costs before and after a definitive diagnosis of FND. Studies showed an excess annual cost associated with FND (range $4,964-$86,722 2021 US dollars), which consisted of both direct and large indirect costs. Studies showed promise that interventions, including provision of a definitive diagnosis, could reduce this cost (range 9%-90.7%). No cost-effective treatments were identified. Study comparison was limited by study design and location heterogeneity. DISCUSSION: FND is associated with a significant use of health care resources, resulting in economic costs to both the patient and the taxpayer and intangible losses. Interventions, including accurate diagnosis, seem to offer an avenue toward reducing these costs.