A psychiatric assessment has been performed on every student in the study in a hospital in Denmark. These took into account the typical range of information required from an assessment from multiple sources and across multiple settings. Considering the medical history, diagnostic interviews, and test results, all students participating are diagnosed with Attention Deficit Hyperactivity Disorder (ADHD) and not ASD or with an IQ of less than 70. Behavioral problems are diagnosed in the hospital or described in the school records.