[1] Dunner went to Washington University School of Medicine, where the psychiatry department was run along biological lines by Eli Robins.
After residency in Philadelphia and back at St Louis, he worked at the National Institute for Mental Health for two years.
Along with fellow researchers Frederick K. Goodwin and Elliot S. Gershon he developed the concept of what they called Bipolar II Disorder.
[2] He then went to New York for eight years to work with Ronald R. Fieve on studies of Bipolar disorder and the emerging Lithium treatment, and developed the concept of 'rapid cycling' for bipolar disorder which was found to show less response to Lithium (he credits Canadian scientist Harvey Stancer for first noticing the connection a year prior).
Since his medical residency he has been "involved in clinical studies of every single drug on the US market at least once, if not many times".