Functional neurological disorders (FNDs) represent a significant source of disability, frequently marked by misdiagnosis and delayed or poorly communicated diagnoses. This can lead to ineffective treatments, iatrogenic harm, and unnecessary healthcare expenditures, ultimately resulting in unfavorable patient outcomes.
The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), has adopted the term Functional Neurological Symptom Disorder/Conversion Disorder, replacing “psychogenic” with “functional.” Crucially, the DSM-5 removed the requirement for psychological stress as a prerequisite for FND diagnosis. Diagnosis now focuses on identifying specific, positive neurological signs of FNDs, rather than relying on the presence or absence of psychological stressors or suggestive historical details. This updated model acknowledges a broader spectrum of predisposing factors, including physical trauma, medical illnesses, and physiological or psychophysiological events. The model suggests that strong beliefs and expectations related to these events can contribute to abnormal sensory predictions and heightened body awareness. Neurobiological research indicates that FND is associated with hypoactivation of the supplementary motor area and impaired connectivity with brain regions responsible for movement selection, inhibition, and the sense of agency.
Encouragingly, evidence supports the effectiveness of targeted physical rehabilitation and psychological interventions, both independently and in combination. However, robust clinical trial data remains limited.
In conclusion, functional neurological disorders are a frequently overlooked yet potentially reversible cause of disability. Further research is essential to determine optimal treatment dosages and durations, the benefits of combined and multidisciplinary approaches, and to personalize therapeutic strategies for individual patients.
