My University's communications office reserves "Dr" for MDs only - is this common? I recently became aware that, when writing an article, my university's communications office reserves the prefix "Dr" for only those individuals with MD degrees. 

For example, if Jane Smith holds a PhD, an article published through this office would state, "Jane Smith researches memory..." instead of "Dr Jane Smith researches memory" or "Jane Smith, PhD, researches memory". But if Jane holds an MD, the statement would be written, "Dr Jane Smith researches memory."  

The communication office's response to this is that "Dr" is most often associated with medical doctors; also, the AP guide recommends this approach. 

First, is this a phenomenon in other institutions?  I am at a large public university in the US, for reference.  Second, the office may be correct that "Dr" is associated most with physicians, but does anyone have a citation for that?  Third, I couldn't find this in the AP guide--any hints on where to look?
The AP style guide does say that "Dr." is used to indicate medical doctor, and that academic degree (Jane Doe, Ph.D.) is used to indicate doctorates. That said, if you don't like that policy, you can point out:

1) It is standard etiquette to use the title a person prefers, and rude to do otherwise.

2) The AP style guide is just one convention among many. Lots of institutions have their own policies (e.g. NASA's communication office has the exact opposite convention, referring to Ph.D.'s as "Dr." and referring to medical doctors as "Jane Doe, M.D."). Several high-profile press institutions (including the New York Times and Wall Street Journal) do not follow the AP style guide in this regard as well.

https://en.wikipedia.org/wiki/Doctor_(title)#United_States