A “medical doctor” is a physician who has had years of training to understand the diagnosis, treatment and prevention of disease. The basic training of a physician specialist includes four years of premedical education in a college or university, four years of medical school and, after receiving the M.D. degree, at least three years of specialty training under supervision (called a residency). Training in certain subspecialties can take an additional two to three years.
The process most widely used by physicians to tell whether and why you are sick is to ask you, and/or your family members, questions about your health and your past medical history. This process, called “taking a history,” is usually followed by an appropriate examination of your body (a physical examination) to determine how well it is functioning and whether there are signs of disease. Doctors also use a variety of tests such as X-rays, other imaging techniques and additional procedures to evaluate your health and identify any diseases or other health problems that may be present. Some of these diagnostic procedures (e.g., cardiac catheterization, CAT scans and biopsy of body tissues) are very complicated and require many years of training in order to use them safely and accurately.
After the diagnostic process is completed, the doctor will recommend what treatment is needed, if any. Treatment may involve surgery (there are many types of surgical specialists), medication or other complex procedures.
The complexity of the body’s structure and the way it functions calls for high levels of skill in understanding body systems and in knowing the effect that each system has on the whole, in health and in disease. That is why most physicians choose to specialize.
Specialists are physicians who have chosen a specific area of medicine and have completed a residency in that field. Specialization in medicine combined with continued medical education is necessary because of the rapidly expanding body of knowledge about health and illness and the constantly changing techniques for the prevention, diagnosis and treatment of disease.
Subspecialists are physicians who have completed training in a general medical specialty and then take additional training in a more specific subarea of that specialty, called a subspecialty. This training increases the depth of knowledge of the specialist in that particular field. For example, cardiology is a subspecialty of internal medicine, pediatric surgery is a subspecialty of surgery, and child and adolescent psychiatry is a subspecialty of psychiatry. The training of a subspecialist within a specialty requires an additional one or more years of full-time education.