any psychologist or psychiatrist that I have been to for the first time has introduced themselves as "Dr. Timbucktu" when that happens its expected the DR wants to be called his/her official name. With those that I have been with longer they eventually use their first name for example on my answering machine - "hi this is Tom Timbucktu and I am calling to reschedule our appointment" that tells me it is now ok to use first name basis because he has referred to himself by first name instead of official title.