A systematic review of functional neurological disorder in transgender people.

Background: Trans and gender diverse people may be more likely to have a functional neurological disorder (FND), although the reasons for this are unclear. This systematic review examines the relationship between trans people and FND, to determine if one population is overrepresented in the other, and if gender affirming-care affects symptoms of FND. Methods: A systematic review was conducted as per PRISMA guidelines. Searches were performed on OVID (MEDLINE), PsycINFO, and Web of Science. Studies included focused on both FND and trans people, had subjects of any age, and were original research articles. When the study referred to somatic symptom and related disorders it was included. Study quality was assessed using JBI's critical appraisal tools. Results: Fourteen studies were included. Seven examined the prevalence of FND (or likely FND) in trans people, or of trans people in people in FND or (likely FND patient populations), and seven were case studies or series of trans people with probable FND (total cases = 20). Trans people made up 3-45% of people with FND; somatic symptom and related disorders were present in 6-9.7% of trans people (compared to 5-7% in the general population). Fifteen of the 20 cases were trans people assigned female at birth. Ten of the 20 cases developed FND prior to their social gender affirmation, and seven of those ten's symptoms resolved with gender affirmation. Discussion: Trans people were more likely to develop FND, and somatic symptom and related disorders were slightly overrepresented in trans people. Gender affirmation can lead to resolution of FND symptoms. Trans people appear to make up a considerable proportion of people with FND. FND treatment services need to consider how they provide trans affirming services.