Recent advances in genomics have revealed that many polygenetic diseases are caused by complex combinations of many common variants with individually small effects. Thus, building informative disease models requires the interrogation of many patient-derived genetic backgrounds in a disease-relevant cell type. Current approaches to obtaining human neurons are not easy to scale to many patients. Here we describe a facile, one-step conversion of human adult peripheral blood T cells directly into functional neurons using episomal vectors without the need for previous in vitro expansion. This approach is more amenable than induced pluripotent stem cell-based approaches for application to larger cohorts of individuals and will enable the development of functional assays to study complex human brain diseases.