Child psychiatrist Dr. Jeremy Veenstra-VanderWeele explores the two main approaches for developing autism medicines. The first and most common approach is to evaluate a treatment in the total group of people affected by ASD, usually with a small number excluded due to the presence of a known genetic syndrome. The second approach is almost the exact opposite, to study a medication for ASD-related symptoms in a defined genetic syndrome that confers substantial risk of ASD but comprises less than 2% of individuals with ASD. Transformative treatments, though possibly not "cures," seem most likely to emerge from the second approach, but in a small group of children. In contrast, if the first approach is successful, we can expect a treatment that benefits a larger group of children, but likely benefits them less. (#29512)