William T. Carpenter is an American psychiatrist, a pioneer in the fields of psychiatry and pharmacology who served as an expert witness in the John W. Hinckley trial for the attempted assassination of U.S. President Ronald Reagan.
[1] He began his research career with the National Institute of Mental Health Intramural Program in 1966, using neuroendocrine strategies to study the psychobiology of affective disorders.
[1] In 1966, Carpenter took a psychiatric researcher position at the National Institute of Mental Health (NIMH) in Bethesda, Maryland, where he studied the psychobiology of affective disorders.
[9] He is a past-president of the American College of Neuropsychopharmacology and participated in the founding of the National Alliance for Research on Schizophrenia and Depression, for which he has chaired its scientific program committee.
As the defense psychiatrist, Carpenter interviewed Hinckley for a total of 45 hours and took the stand at the trial to provide a compelling three days of testimony.