Objective:

To better characterize Functional Neurological Disorder (FND) within the United States, we completed a retrospective longitudinal analysis of patient demographics and setting of initial diagnosis, as reported within the TriNetX database. Diagnostic rates of FND were also compared to that of Generalized Anxiety Disorder (GAD).

Background:

Despite its prevalence, gaps exist in understanding demographics and diagnostic patterns in FND.

Design/Methods:

We identified 116,145 patients with FND (records from 1978-2024) using the codes ICD-9 300.11, and ICD-10 F44.4 to F44.7, and  2,715,389 patients with GAD (records from 1981-2024) using the codes ICD-9 300.02 and ICD-10 F41.1. We analyzed the number of annual new cases for both conditions and examined longitudinal trends for demographic factors (age, sex, race, ethnicity) and diagnostic settings (inpatient vs. outpatient) for FND. Rate ratios were used to assess annual changes in these characteristics; we conducted a simple linear least squares regression (two-sided, α = 0.05) to determine any significant changes over time in rate ratios.

Results:

The mean age at FND diagnosis was 38.90 years (SD = 19.28), with the majority being female (71%), White (65%), and non-Hispanic (72%). Longitudinally, female diagnosis rates did not change significantly compared to males, while Hispanic diagnosis rates increased significantly compared to Non-Hispanic patients. Diagnosis rates for all races increased, except for White versus Black patients, which decreased, though not significantly. Most FND diagnoses were made in outpatient settings (55%), but the proportion of inpatient diagnoses increased over time. The number of annual new cases for both FND and GAD rose, with the GAD diagnosis rate surpassing FND over time.

Conclusions:

Enhancing the understanding of FND epidemiology can lead to improved, personalized, and more equitable patient care through better allocation of resources, improving diagnostic and treatment costs, and improving clinician education on this condition.