Is a DO a type of doctor similar to a chiropractor?
In the United States, a DO (doctor of osteopathy) is more like an MD (medical doctor) than a DC (chiropractor). A DO completes a medical residency like a medical doctor and graduates to treat the same conditions with the same tools. One difference is that a DO has training in joint manipulation techniques that they may use on some patients.
The use of joint manipulation is one commonality between DO and DC in the United States. However, DCs use joint manipulation as one of their most common interventions, whereas DOs use it very limited nowadays. While DCs complete 8 years of university like DO and MD, they do not complete a hospital residency like DO and MDs. Finally, chiropractors treat different conditions than DO and MDs. Chiropractors treat primarily irritating musculoskeletal conditions (like back pain, carpal tunnel syndrome, headaches, etc) whereas medical doctors and doctors of osteopathy often treat emergency conditions (like heart attacks, stroke, cancer).
Doctors of Osteopathy in the United States are actually called Doctors of Osteopathic Medicine (D.O.) and have the same practicing rights as Medical Doctors (M.D.). They hold the same residency programs and many actually matriculate into M.D. residency programs in order to enter some of the more competitive specialties. They differ little from M.D's anymore as medicine has moved towards prevention and whole person treatment in the last 40 years. The key difference is that they are trained in OMM (Osteopathic Manual Manipulation) which usually is more gentile and used with less frequency than the manipulation used by chiropractors. Unlike Chiropractors (D.C.), D.O.'s can practice a full range of medicine and have medical schools with competitive entrance requirements.
While the requirements to enter osteopathic medical school used to be much lower than most M.D. schools, recent years have closed the gaps drastically in GPA and MCAT (Medical College Admissions Test) scores. Some recent osteopathic schools have GPA averages above 3.7 (which is average for M.D. schools) and MCAT scores a few points behind the average M.D. schools (for example Des Moines University located in Iowa). The disparity between GPA and MCAT scores has been a trend of D.O. schools, since they usually matriculate more non-traditional students. Also, the majority of D.O. matriculates plan and later practice family practice or internal medicine. Interestingly enough, if one considers the MCAT difference between D.O. and M.D. schools, they will note that most M.D. schools who produce similar percentages of family practice or internal medicine doctors usually have very similar MCAT scores, but with lower GPA scores on average. D.O.'s are becoming more popular but currently have less than 30 schools (more being planned) while M.D. schools are about 130. D.O.s are currently about 10% of the practicing physician work force in the United States. Both M.D.s and D.O.s represent the top 25% of their undergraduate classes. Out side of the United States, D.O.s are usually more similar to chiropractors in their scope of practice. There is an increasingly greater amount of foreign countries that will give D.O.'s full practice rights, however few D.O.s have petitioned, leaving some countries unknown as to whether or not they will allow D.O.s trained in the U.S. to have full practice. However, D.O.s in a program like doctors without borders have no restrictions.
Now, chiropractors do not have similar statistics or medical training. In fact, the average chiropractic school is significantly behind both M.D. and D.O. schools. The average is somewhere close to a 3.5 GPA and matriculation is not competitive. No entrance exam or letters of recommendation are required. This tends to create a negative feeling towards them by many of the other professions.
Traditionally, osteopathic medicine started as a social movement away from overuse of dangerous drugs and questionable medical practices in the late 1800's. While autonomy existed rather heavily in the beginning, the majority of current D.O.'s do not use OMM on a regular basis. Currently, they are increasingly represented in competitive specialties even thought the majority are still in family practice or internal medicine. Chiropractics started only a few years after osteopathy but has failed to become a legitimate option to practice medicine as a physician.