Medium is based on a true story, but it isn't based on Allison Dubois. Medium is based on another woman. Most of the crimes depicted in Medium episodes are based on real crimes this other woman was either consulted on by an employee of the U.S. Attorney's Office or spontaneously had psychic dreams about. I know this because I am the woman Medium is based on. If you were to look up crimes that happened in Arizona, Texas, New York, and the Washington, D.C. area between 1982 and 1984, then you would find most of the crimes that are depicted in Medium. At the time, Allison and Joe Dubois were children.