Background Functional Neurological Disorder (FND) encompasses motor, cognitive, and sensory symptoms resulting from disruptions in brain-body communication. Emerging research suggests a higher-than-expected occurrence of autism in FND, potentially due to shared cognitive mechanisms and overlapping comorbidities. However, large-scale characterisation of this dual-diagnosis is lacking. Methods Using de-identified health records from the TriNetX research network, we identified children and adults with both FND and autism (‘FND + Autism’), comparing them to individuals with FND only (‘FND-only’) and autism only (‘Autism-only’). We examined psychiatric comorbidities (e.g. mood, anxiety, post-traumatic stress disorder, personality disorders, obsessive–compulsive disorder), intellectual disability and ADHD. Results Of 220,312 individuals with an FND diagnosis, and 674,971 individuals with an autism diagnosis, 5,152 (2.3% of FND, 0.76% of autism) had both FND and autism. The rates of autism were therefore 6 times higher in FND compared to the base rates of the TriNetX population. Most were diagnosed with autism before FND, with over one-third diagnosed in childhood. Functional seizures were the most common FND subtype, and were more frequent in FND + Autism than FND-only (adults: 52% vs. 44%; children: 47% vs. 42%). Comorbidity across all psychiatric conditions was significantly higher in FND + Autism compared to both comparison groups. ADHD was particularly elevated in FND + Autism (adults: 50% vs. 13% FND-only, 36% Autism-only; children: 64% vs. 21% FND-only, 41% Autism-only). Conclusions This study presents the largest dataset to date characterising individuals with co-occurring FND and autism. Findings are consistent with previous findings of higher rates of autism in people with FND and reveal a potentially distinct clinical profile, marked by elevated rates of ADHD and psychiatric comorbidities, and increased occurrence of functional seizures compared to FND- or Autism-only groups. Recognising this overlap may improve diagnosis, clinical care, and understanding of mechanisms underlying the co-occurrence of FND and autism.

Background In this qualitative study, we aimed to obtain and synthesise the views of patients with functional neurological disorder (FND), their caregivers, and relevant healthcare professionals (HCPs...

What does TRD tell us about the assumptions guiding clinical care?