College students who are interested in health care and who excel in science often see one path open to them: medical school. However, becoming a licensed and board-certified physician typically requires four years at either an M.D. or a D.O. program, plus three to five years in a residency focused on a medical specialty like psychiatry or surgery.
Aspiring doctors who want to sub-specialize in a very specific area of medicine, such as addiction psychiatry or pediatric surgery, may elect to pursue a fellowship in that field, which means that their medical training will last about a decade.