A study by Harvard Medical School, published in the August 21, 2001 issue of the Annals of Internal Medicine, examined trends in the use of 20 different CAMs (Complementary and Alternative Medicine), covering everything from acupuncture to yoga, among representative groups across the U.S.  The study continued to show that the use of what the study termed "CAM" has continued to rise. The study was done by a nationally representative telephone survey of 2055 people.

The results showed that approximately 3 of every 10 respondents in the pre–baby boom cohort, 5 of 10 in the baby boom cohort, and 7 of 10 in the post–baby boom cohort reported using some type of CAM therapy by age 33 years.  The study also noted that of the respondents who ever used a CAM therapy, nearly half continued to use it many years later. A wide range of individual CAM therapies increased in use over time, and the growth was similar across all major sociodemographic sectors of the study population.

The term CAM is a medically created term that may itself not be very representative as most of the procedures included in the list are neither complimentary or alternatives to medicine.  In fact many such as chiropractic are completely separate primary health care professions that are not even considered alternative in many references.

The conclusion of the Harvard study as published in the Annals of Internal Medicine, was that the "Use of CAM therapies by a large proportion of the study sample is the result of a secular trend that began at least a half century ago. This trend suggests a continuing demand for CAM therapies that will affect health care delivery for the foreseeable future."