In the United States, psychiatrists train by going to university first, then they go to Medical School for 4 years. Then they must complete a residency. When they graduate, they get to use the initials M.D. or D.O. after their names. Then these doctors specialize by training for 3 or 4 years in Psychiatry. In other countries psychiatrists train in similar ways but may not have to go to a separate university and medical school.