Interesting question...
It is my experience that the release of confidential information regarding indentification / diagnosis / treatment pertaining to alcoholism, drug addiction, and HIV are protected under federal law. CFR 42 to be exact.
I am familiar with "Release of Confidentiality" forms that ask if the patient/client authorizes release of this information. Usually the patient/client must sign and initial this release of information. The Care Provider cannot withhold care should the patient/client refuse to grant this permission.
These forms are all part of the "Intake Process".
I could be wrong, but that is my understanding of the law.
Now you have my curiosity up... I am going to check into this more...