" The difference between doctors and nurses lies in the training of each. Doctors graduate from college, then spend four years in medical school. After medical school comes residency, a minimum of three years for primary care careers such as family practice and pediatrics. Specialties like surgery and psychiatry take longer, usually at least five years beyond medical school. And subspecialties, neurosurgery for example, take even longer. A doctor spends at least seven and as many ...