Structured clinical diagnostic assessment reveals autism spectrum disorder in adults with functional neurological disorder.

This small study looked at 16 adults with functional neurological disorder (FND) to see how many also had autism. Half of the participants (8 people) were found to likely have autism. Those with autism had more anxiety, felt disconnected from themselves more often, and worked harder to mask their autistic traits. They also experienced more sensory problems. The research suggests autism might be common in people with FND but often goes unnoticed.

This study examined autism spectrum disorder (ASD) prevalence in adults with functional neurological disorder (FND) at a specialist clinic. Using comprehensive assessments including ADOS-IV interviews and DSM-5 criteria, researchers found that 50% (8 of 16) participants met criteria for clinically probable ASD. Those with probable ASD had younger symptom onset, longer diagnostic delays, and significantly higher anxiety, dissociation, and camouflaging behaviours. Sensory symptoms were more common in the ASD group (62.5% vs 12.5%).

The findings suggest ASD frequently co-occurs with FND but remains under-recognised, highlighting the need for routine neurodevelopmental screening and informed care approaches.

Findings suggest need for routine autism screening in FND clinics and neurodevelopmentally-informed care approaches. Clinicians should consider autism assessment for FND patients with early symptom onset, diagnostic delays, high anxiety, dissociation, or prominent sensory symptoms. Larger studies needed to confirm these preliminary results.

Very small sample size (n=16) limits generalisability. Observational design prevents causal inferences. Multiple comparisons increase risk of false positives. Single-site recruitment may introduce selection bias. Lacks control groups for broader comparison.

Emerging evidence suggests a link between Autism Spectrum Disorder (ASD) and Functional Neurological Disorder (FND), underscoring the importance of considering neurodevelopmental traits in neurological care. This study examined the prevalence of clinically probable ASD (CP-ASD) in a specialist FND clinic and explored its associations with symptom presentation, mental health, alexithymia and interoceptive awareness. Sixteen consecutively recruited adults with FND underwent comprehensive ASD assessment, including self-report questionnaires (RAADS-R, AdAS Spectrum), observational interview (ADOS-IV), and evaluation against DSM-5 criteria. Additional validated psychometric measures assessed anxiety (GAD-7), depression (PHQ-9), dissociation (Cambridge Depersonalization Scale, CDS), alexithymia (TAS-20), camouflaging (CAT-Q), and interoceptive sensibility (MAIA-2).

Half of the participants (n = 8) met criteria for CP-ASD. Compared with the non-CP-ASD group, the CP-ASD group had a younger age at symptom onset and a longer interval from onset to FND diagnosis. After correction for multiple comparisons, significant group differences remained for anxiety (GAD-7), dissociation (CDS), and camouflaging behaviours (CAT-Q total, Compensation, and Assimilation subscales). Several further differences reached uncorrected significance with large effect sizes, including alexithymia (TAS-20) and the MAIA-2 Not Worrying and Emotional Awareness subscales, but did not survive correction and should be considered exploratory.

Among functional symptom types, only sensory symptoms differed, being more prevalent in the CP-ASD group (62.5% vs 12.5%, p =.021), while treatment response did not differ between groups. . These findings suggest that ASD may frequently co-exist with FND but remain under-recognised. Incorporating routine screening and neurodevelopmentally informed care could improve diagnostic accuracy and support more personalised interventions. Larger, adequately powered studies are needed to confirm these preliminary results and to clarify further the role of neurodevelopmental factors in the onset, persistence, and treatment response of FND.