Describe the demographics and clinical characteristics of individuals diagnosed with functional movement disorders (FMDs) in the University of Colorado Health (UCH) system, with particular focus on rates of co-morbid psychiatric diagnoses.

FMD is an increasingly recognized condition characterized by abnormal movements incongruent with a known neurologic cause. Despite its high prevalence, FMD remains poorly characterized, with only a few large cohorts described in the literature. Furthermore, while psychiatric co-morbidities are thought to be associated with FMD, the evidence to support this conclusion is weak.

We conducted a retrospective study using data from the University of Colorado Health Data Compass platform, with 847 patients identified with FMD by diagnosis codes. Queried medical encounters took place between 2011-2018. De-identified demographic and clinical features, including co-morbid psychiatric diagnoses, were queried from medical records of identified patients. 

Patients were disproportionately female (69.8%), white (73.9%), average age of 51.9 years (SD = 17.6), and 72.0% had a concurrent psychiatric diagnosis. FMD phenomenology did not significantly differ between patients with and without psychiatric diagnoses. 54.4% of patients had a single FMD phenomenology (weakness 41.0%, gait abnormality 23.6%, tremor 13.7%, dystonia 9.1%, and ataxia 2.6%). Multiple FMD phenomenologies were present in 45.6% of patients, associated with significantly higher rates of anxiety disorders (p < 0.001, OR = 2.04, 95% CI: 1.55, 2.69) and post-traumatic stress disorder (PTSD; p = 0.005, OR = 1.61, 95% CI: 1.16, 2.24).

To date, this is the largest descriptive cohort of FMD and demonstrates a high frequency of co-morbid psychiatric diagnoses in this population. However, the phenomenological presentation of FMD did not differ between those with and without psychiatric diagnoses. The presence of multiple FMD phenomenologies was associated with more co-morbid anxiety and PTSD, though, a connection that should be explored with future prospective studies to establish the direction of this relationship.