Pregnenolone has been used safely in research studies involving individuals with schizophrenia. In the proposed trial, we hope to examine the tolerability of pregnenolone in adults with autism. We hope to see improvement in behavioral outcomes as measured by standardized behavioral measures. Further, we will measure concentrations of pregnenolone and related neuroactive compounds in the blood. The use of pregnenolone has been studied in a number of mental disorders but not autism. Thus, we hope the study will identify new avenues of research for the treatment of autism.