After completing his Psychiatry residency training, Dr. Amsel completed research fellowships at Columbia University in Mental Health Statistics and in Child Psychiatry Research.  He also joined the faculty of Columbia University in 1992 as a clinical and research psychiatrist, where he worked on suicide risk factors. After 9/11, Dr. Amsel joined the Trauma Studies and Services (TSS) Division at the New York Psychiatric Institute, as the Co-Director for Dissemination. Later he joined the Global Psychiatric Epidemiology Group (GPEG) at Columbia studying the effects of childhood stress, such as 9/11 exposure or exposure to the Criminal Justice System, on child and adolescent mental health. In that context he recently coedited a book entitled, An International Perspective on Disasters and Children's Mental Health (Springer, 2019).

Throughout his medical career, Dr. Amsel has worked at the interface of psychiatry and physical medicine. As a hospital and emergency room psychiatrist for over thirty years, he was responsible for the total health of patients under his care. This experience led him to work with the REACH Institute where he helped develop a training program for Primary Care Physicians (PCP) on how to integrate mental health into primary care practice. He also co-developed the REACH communications course with Marjorie Heyman, Ph.D. Dr. Amsel has continued to be actively involved in REACH training for more than a decade.