Internal medicine grew out of the increasing application of scientific knowledge into the practice of medicine starting in the late 1800s. The training an internist receives is both broad and deep and qualifies them to manage very complex medical issues, and in many cases, perform advanced clinical procedures.
Required internal medicine training focuses on common general medical conditions, but also includes significant experience in each of the internal medicine subspecialties (such as endocrinology, rheumatology, and infectious diseases) and neurology. Trainees must also gain adequate experience in psychiatry, dermatology, ophthalmology, office gynecology, otorhinolaryngology, non-operative orthopedics, palliative medicine, sleep medicine, geriatrics, and rehabilitation medicine to comprehensively care for adults.
Because internal medicine education focuses only on adults, training in adult medical issues is comprehensive and deep. By contrast, family medicine education is broader in nature than internal medicine since it involves training in the care of children and procedures and services often provided by other specialties.
Internal medicine physicians are recognized as experts in diagnosis, treatment of chronic illness, health promotion and disease prevention and they are often called upon to act as consultants to other physicians to help solve puzzling diagnostic problems.
General internists are equipped to deal with whatever problem a patient brings—no matter how common or rare, or how simple or complex. They are specially trained to solve puzzling diagnostic problems and can handle severe chronic illnesses and situations where several different illnesses may strike at the same time.
Some internists choose to take additional training to "subspecialize" in a more focused area of internal medicine. This training usually requires an additional one to three years beyond the basic three year internal medicine residency.