Autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) can be traced back to specific early childhood temperament patterns. However, no unique pattern has been identified for their co-occurrence. Given that children with both traits often require more clinical attention, this study aimed to discover such patterns by examining three temperament domains measured during early childhood-Surgency/Extraversion (SE), Negative Affectivity (NA), and Effortful Control (EC)-and…