That's because unlike the brain of an adult or even an older child, a 12- or 18-month-old's brain is, in a sense, highly reprogrammable—that is, it responds well to treatments designed to permanently change basic patterns of thought and behavior. "All the evidence we have suggests that outcomes for these children will be better with an earlier diagnosis, before they reach 18 months, if possible," says Christopher Gillberg, a child psychiatrist at Gothenburg University in Sweden.