Epilepsy or seizure disorders happen relatively frequently in individuals with autism spectrum disorders (ASD) and seizures are always treated with medication. However, abnormalities on the electroencephalogram (EEG) can also be present in ASD even when there are no seizures. The need for treatment of these EEG abnormalities is unclear. We believe that these EEG epileptiform discharges may represent an important biomarker in some individuals with ASD and want to explore them as a target for treatment. Studies suggest that epileptiform discharges contribute to problems in attention, language and behavior. We propose to test whether there is a positive effect of treating children with ASD and epileptiform EEGs using an anti-seizure medication that is known to help normalize the EEG (Depakote). Thirty subjects ages 4-8 will be recruited from 2 large autism centers (Children’s Hospital Boston and Vanderbilt University). Subjects with epilepsy and any metabolic or medical conditions will be excluded. All subjects will have an overnight EEG to confirm they have epileptiform discharges. Subjects will be in the study for 26 weeks receiving active drug for 12 weeks and placebo (inactive substance) for 12 weeks. Subjects will not know which they are getting. EEGs and behavioral assessments will be done at the beginning, middle, and the end. We hope to show that administration of Depakote will reduce the number of epileptiform EEG discharges. We also want to show that Depakote improves a wide range of behavioral measures including: language, mood, irritability, attention, motor, sensory, adaptive function and core ASD behaviors. Because there is a known relationship between Depakote, EEG discharges and sleep, we will look at changes in sleep and how these measures relate as well. Finally we will test a special EEG to see if brain connectivity measures change and are related to behavioral improvements.