A: It takes a long time for new therapies to get accepted. The U.S. National Institutes of Health (NIH) calls this the “translational gap” between research and patient. A report by the Institute of Medicine (IOM; now called the National Academy of Medicine) explained this phenomenon: “Scientific knowledge about best care is not applied systematically or expeditiously to clinical practice. It now takes an average of 17 years for new knowledge generated by randomized controlled trials to be incorporated into practice, and even then application is highly uneven.”
Here is the citation for the full IOM report: Committee on Quality of Health Care in America, Institute of Medicine. (2001). Crossing the quality chasm: A new health system for the 21st century. Washington, DC: National Academy Press.
For further information on this subject, see the article by Dawson Church and colleagues on clinical innovations: Church, D., Feinstein, D., Palmer-Hoffman, J., Stein, P. K., & Tranguch, A. (2014). Empirically supported psychological treatments: The challenge of evaluating clinical innovations. Journal of Nervous and Mental Disease, 202(10), 699—709. doi:10.1097/NMD.0000000000000188
