Crowell JA, et al. - In this study, a case series in which low-dose fluoxetine was beneficial for children with autism spectrum disorder (ASD) was presented. These children were found to respond very well to low dose fluoxetine. There were many reports and trials showing that fluoxetine could be beneficial in treating ASD symptoms. However, the response to very low dose and rapid onset observed here suggested a mechanism of action differing from the slower onset, higher dose treatment of depression, and anxiety in typically developing individuals. To identify people who were very sensitive to medications, including those with ASD and, thus, those who could only benefit with a very low dose, research was required.