A Dynamical Reinterpretation of Functional Neurological Disorders

Functional Neurological Disorders (FNDs) present with genuine and often disabling motor, sensory, and autonomic symptoms in the absence of structural neurological lesions. Existing accounts alternately frame FND as psychogenic, misdiagnosed organic disease or a disturbance of predictive processing. What’s missing is a formally unified dynamical framework. We develop a multilevel control-theoretic model in which peripheral physiology (x), cortical predictive states (m) and policy-level agency (a) interact through precision-weighted free-energy minimization. From a minimal variational formulation incorporating prediction error, energetic control cost and slow allostatic load, we derive a compressed four-state dynamical system characterized by autonomic volatility (V), precision imbalance (ΔΠ), control burden (B) and load (L). Analyses of the Jacobian and Routh–Hurwitz stability conditions reveal how pathological attractors emerge through positive feedback between volatility, maladaptive precision weighting and effortful control. Functional symptoms arise not as fabrication or structural lesion but as stable regimes of a nonlinear regulatory system. The model generates clinically interpretable stability criteria, clarifies the interaction between autonomic retraining, exposure-based recalibration, behavioral activation and physical repair. It provides a principled bridge between neurobiology, computational psychiatry and philosophical accounts of mind-body interaction. We reconceptualize FNDs as disorders of regulation rather than representation, arising from lawful dynamics within a precision-weighted, energy-constrained organism.