Functional neurological disorder: characterization, diagnosis, and outcome predictors in a Brazilian cohort

Functional neurological disorder (FND) is a prevalent, disabling neuropsychiatric condition recognized as a distinct clinical entity characterized by positive neurological signs. Despite growing international research, Brazilian data on this disoder remain scarce and predictors of clinical outcomes are poorly established.

To describe the clinical profile of patients with FND in a Brazilian outpatient cohort and investigate predictors of functional improvement.

We retrospectively analyzed medical records of 29 patients diagnosed with FND at the Somatic Disorders Outpatient Unit (SOMA) of the Institute of Psychiatry of Hospital das Clínicas, Universidade de São Paulo (IPq-HCFMUSP). Psychiatric diagnoses were established by board-certified psychiatrists using Diagnostic and Statistical Manual of Mental Disorders 5^th edition (DSM-5) criteria and structured clinical interview. Clinical features, psychiatric comorbidities, and therapeutic interventions were recorded. A multivariable Firth's bias-reduced logistic regression identified predictors of functional improvement.

The cohort included predominantly cisgender women (75.9%), with a mean age of 33.6 ± 13 years. The most common presentations were pain (51.7%) and paresis (48.3%); others included psychogenic nonepileptic seizures (PNES), sensory disturbances, and speech alterations. The most frequent positive neurological sign was Hoover's sign (20.7%). Psychiatric comorbidities included mood (44.8%), anxiety (20.7%), and personality disorders (10.3%). Overall, 31% achieved functional improvement. Group psychotherapy with a psychodynamic orientation significantly increased odds of improvement (p = 0.036); eutony also showed a positive association (odds ratio [OR] = 5.68; p < 0.05). Absence of mood disorders was associated with lower odds of improvement (OR = 0.36; 95% confidence interval: 0.11-0.99; p = 0.048).

The present is the first Brazilian study to employ multivariable modeling to identify predictors of functional outcomes in FND. Group psychotherapy and eutony were associated with improvement, reinforcing the value of multidisciplinary approaches and highlighting the importance of Latin American clinical data.