“Missed” cases with neurodevelopmental disorders (NDDs) within adult psychiatry services have attracted increasing attention in the last decade. Key questions have been what the prevalence of NDDs (particularly attention-deficit/hyperactivity disorder/ADHD and autism spectrum disorder/ASD) is, and what the clinical and gender characteristics of those with NDD in adult psychiatry are. All first-time attenders at an adult psychiatry clinic serving 18-25 years old were invited to take part in the…