In his decades working as a forensic psychiatrist, Dr. Richard Coons of Austin has testified at dozens of death penalty trials across Texas in which he opined about how defendants would behave in the future.
Dr. Coons is in a situation similar to Dr. Grigson (a.k.a Dr. Death). Grigson was expelled from the APA for ethics violations. Grigson concluded in the case of Randal Dale Adams that Adams would kill again if released from prison. The only problem with this predication was that Adams had never killed anyone in the first place. He was exonerated and released from Texas Death Row after serving nearly 10 years.
The bottom line is that it is impossible to accurately predict future dangerousness. The American Psychiatric Association filed amicus briefs that noted
Psychiatrists should not be permitted to offer a prediction concerning the long-term future dangerousness of a defendant in a capital case, at least in those circumstances where the psychiatrist purports to be testifying as a medical expert possessing predictive expertise in this area. Although psychiatric assessments may permit shortterm predictions of violent or assaultive behavior, medical knowledge has simply not advanced to the point where long-term predictions -- the type of testimony at issue in this case - -may be made with even reasonable accuracy. The large body of research in this area indicates that, even under the best of conditions, psychiatric predictions of long-term future dangerousness are wrong in at least two out of every three cases.