Based on the known effects of MDMA, as well as individual reports from autistic adults, this exploratory study will focus on enhancing functional skills in this underserved population, who tend to experience greater anxiety, depression and victimization than typically developing adults. The main objective of this study is to collect safety data to examine whether MDMA-assisted therapy will be tolerated and to estimate effect size of symptom reduction in social anxiety and other psychiatric symptoms that are common in the adult autistic population as evaluated by standard clinical measures. The primary outcome measure will be change in social anxiety levels as measured by the Lieberman Social Anxiety Scale (LSAS). Secondary measures include those of social anxiety, anxiety, depression, stress, self-esteem, emotion labeling and recognition, empathy, and quality of life, and blood levels of the hormones oxytocin, arginine vasopressin and cortisol.