Investigating the prevalence of anxiety disorders in autistic adults referred to the neurodevelopmental disorders clinic of Roozbeh hospital using the Structured clinical interview for DSM-5®

Autism spectrum disorder (ASD) is a chronic neurodevelopmental condition linked to significant long-term health consequences. Although ASD is often diagnosed in childhood, many individuals remain undetected until adulthood. The estimated prevalence among adults is similarly high, approximately 11 per 1000 individuals. Anxiety disorders are more common in ASD individuals and may adversely impact quality of life. Overlap between ASD and anxiety symptoms can complicate diagnosis and access to proper treatments, and may account for the differences in reported prevalence between studies. Research on adult ASD in Iran is exceedingly scarce. Therefore, this study aimed to (i) investigate the current prevalence of comorbid anxiety disorders in autistic adults; and (ii) examine the association between autism-trait measures and anxiety symptoms. This descriptive-analytical cross-sectional study included 83 autistic adults from a neurodevelopmental clinic in Tehran (mean age: 26.53 ± 7.17 years; male-to-female ratio: 4.53:1). Data were obtained from participants’ prior records (AQ, RAADS-R, IQ), the Hamilton anxiety rating scale, and the SCID-5 interview. The current prevalence of GAD, SAD, panic disorder, and agoraphobia was 50.6%, 48.2%, 16.9%, and 14.5%, respectively. Significant positive correlations were observed between HAM-A scores and both RAADS-R ( r = 0.49, 95% CI [0.282, 0.654], p < 0.001) and AQ scores ( r = 0.33, 95% CI [0.096, 0.532], p = 0.005). After adjustment for age, sex, and IQ, RAADS-R remained positively associated with HAM-A (B = 0.154, β = 0.419, 95% CI [0.071, 0.237], p < 0.001), as did AQ (B = 0.619, β = 0.345, 95% CI [0.193, 1.045], p = 0.005). Participants with GAD had higher RAADS-R scores than those without GAD (Cohen’s d = 0.765, p = 0.002), while those with SAD had higher RAADS-R (Cohen’s d = 1.111, p < 0.001) and AQ scores (Cohen’s d = 0.593, p = 0.017). This study’s findings indicate a positive association between autism-trait measures and the severity of anxiety disorders as reflected by HAM-A scores. Furthermore, anxiety disorders were highly prevalent among autistic adults attending this tertiary neurodevelopmental clinic. These findings emphasize the need for improved recognition and management of these challenges, development of support programs, and enhanced training of mental health professionals in adult ASD. Not applicable.