Psychiatric disorders such as autism spectrum disorders, schizophrenia and bipolar disorder affect many brain regions and produce a complex array of clinical symptoms. The defects that contribute to these diseases at the the level of single cells and simple networks remain unknown. New laboratory techniques make it possible to study these diseases by inducing neurons artificially from patient fibroblasts. It is now possible to generate limitless numbers of live human neurons from patients with psychiatric disorders. We predict that these studies will ultimately contribute to our understanding of the initiation, progression and treatment of psychiatric disorders.