A C# Monte Carlo simulation exploring how changes in diagnostic criteria affect the estimated prevalence of Functional Neurological Disorder (FND), formerly known as Conversion Disorder (CD).
The project compares:
- DSM-IV criteria for Conversion Disorder
- DSM-5 criteria for Functional Neurological Symptom Disorder (full criteria)
- DSM-5 "rule-in" criteria only (positive signs of incompatibility)
This simulation demonstrates diagnostic expansion when moving from DSM-IV to DSM-5 criteria. In a simulated UK-sized population of 68 million people, the model shows:
- DSM-IV criteria identify roughly 30,000 cases
- DSM-5 full criteria identify roughly 60,000 cases (≈ 2×)
- Rule-in signs only identify roughly 107,000 cases (≈ 3.5×)
The goal is to illustrate how small changes in diagnostic rules — particularly the shift toward positive rule-in signs and the removal of the mandatory psychological stressor requirement — can materially increase the number of diagnosed cases and allow greater co-occurrence with other neurological conditions.
- Probabilistic patient generation using Monte Carlo methods
- Three separate criteria implementations matching DSM-IV and DSM-5
PatientPresentationclass modelling key clinical traits- Easy to modify parameters for sensitivity analysis
- Console output with summary statistics