Currently, brain imaging is more a research tool for understanding how the brain works than it is a diagnostic tool. However, there is increasing evidence that neuroimaging can identify specific dysfunctional brain circuits involved in a person’s depression—circuit signature, or biotype. The technique can also be used to precisely track whether there is restoration of normal function in response to treatment. Psychiatry is gaining a detailed understanding of neural circuit dysfunction in conditions such as anxiety, PTSD, schizophrenia, and attention deficit hyperactivity disorder. Brain imaging may in the future offer a map to treatment for each individual and help identify the circuit disruptors to which each individual is most sensitive. That information can be used to develop strategies for prevention of disorder.