The Title of ‘Doctor’
Doctor, contracted ‘Dr' or 'Dr.,' originates from Latin meaning ‘teacher,’ from docēre ‘to teach.’ Throughout much of the academic world, the term Doctor is an academic title used since the 13th century to refer to someone who has earned a doctoral degree, the highest academic degree conferred by a university. This is normally the Doctor of Philosophy, abbreviated PhD or Ph.D.
Graduates of Quantum University’s PhD degree program have earned their doctoral degree and can, therefore, use the title 'Doctor,' abbreviated 'Dr' or 'Dr.'
But in many English-speaking countries, it is common (starting in the mid-18th century) to refer to physicians by the title of doctor, regardless of whether or not they hold a doctoral-level degree. The word Doctor has long had a secondary meaning in English of physician. A physician is a medical doctor, either an M.D. or D.O., who has completed graduate training and acquired licensing to provide health care. So this can cause some confusion, as all physicians are doctors but not all doctors are physicians.
Quantum University’s degree programs are not equivalent or comparable to a Doctor of Medicine (M.D.), Doctor of Osteopathic Medicine (D.O.), or a Doctor of Naturopathy (N.D.) and therefore our graduates are NOT physicians or naturopaths. [See Scope of Practice & Disclaimer]
Before enrollment, students are encouraged to (and have the responsibility to) consult their own local and state legislature as well as all federal and state licensing or certification boards for the exact laws pertaining to how the designation 'Doctor' or 'Dr' is protected by either professional boards and/or their government.
In the United States, the use of the title 'Doctor' is dependent upon the setting, as this has been a social custom and etiquette debate for many years. The Emily Post Institute advises that "people who have earned a Ph.D. or any other academic, nonmedical doctoral degree have the choice of whether to use ‘Dr.’ both professionally and socially." But many US states now require healthcare providers to clearly and honestly state their level of training, education, and licensing.
Ultimately, the safest and simplest way for a non-physician practitioner to avoid confusing clients is:
They must have a PhD degree in order to use the appellation 'Doctor' or 'Dr.'
They should use post-nominals to clarify the level of education and “define the nature of their doctorate degree."
As an example, when writing and advertising in the United States and Canada, we recommend:
'Dr. Jane Smith, PhD, DNM - Doctor of Natural Medicine.'
The customary abbreviation of ‘Doctor’ is usually written as 'Dr.' in North America, however, the US Postal Service prefers punctuation to be omitted from addresses. We recognize that etiquette states “If post-nominals are given, the full name should be used without ‘Dr.’ prefix” (e.g. Jane Smith, PhD, DNM - Doctor of Natural Medicine.) However, if the ‘Dr’ prefix is used before the full name, we still recommend adding post-nominals for transparency.
 "Doctor.” 2019. Merriam-Webster.com. Retrieved 25 June 2019.
 “Doctor (title)” 2019. Wikipedia.org. Retrieved 25 June 2019.
 Byrnum, William. "When did medical practitioners start to be called 'doctor'?". 28 June 2013. History Extra. Immediate Media Company. Retrieved 25 June 2019.
 Whitlock, Jennifer. Doctors, Residents, Interns, and Attendings: What's the Difference?. 19 May 2019. In verywellhealth.com Retrieved Retrieved 25 June 2019.
 "Professional Titles". Emily Post Institute. Retrieved 25 June 2019.
 Cocchi, Renee. "'Truth in Advertising' legislation for providers growing in popularity". 19 October 2012. Healthcare Business & Technology. Catalyst Media Network. Retrieved 25 June 2019.
 “Post-nominal letters” 2019. Wikipedia.org. Retrieved 25 June 2019.
 "Clarification of the Title "Doctor" in the Hospital Environment D-405.991". American Medical Association. Retrieved 25 June 2019.
 "Punctuation". Publication 28 - Postal Addressing Standards. US Postal Service. May 2015. Retrieved 25 June 2019.
 Vildilill, Will. “Etiquette for the Alphabet Soup of Post-Nominal Letters”. 15 January 2016. LinkedIn.com. Retrieved 25 June 2019.