Game Master Therapist & Game Master Instructor
There are several different methods that therapeutic use of role-playing games can be applied. As the research data, analysis, and experiments progress, keep an eye open for required skill sets that need to be defined for delivering the game sessions in the most effective way for maximum therapeutic benefit.
One approach currently being used is Romach's approach in Israel. They have a "normal" Game Master running the game sessions, and a professionally trained and certified "general" (not RPG specific) therapist observing through a two-way mirror taking notes during the game session. Prior to the game sessions, the therapist meets with the clients, and ascertains their needs. The therapist helps the GM shape an adventure, or series of adventures, targeting the specific needs of all the players in the planned group.
After each game sessions, the therapist reviews the observation notes, and speaks with the GM on ways to shape the game in upcoming sessions to continue targeting the youths' needs.
Another approach is the workshop approach from a California group, that offers groups several days or weeks of directed gaming sessions (I do not have as much information on this group yet).
Another approach I'm considering is the feasibility of some kind of fully trained and certified "Game Master Therapist" (GMT), and/or "Game Master Instructor" (GMI). This would be someone that has both a professional therapy/psychology background and is a skilled Game Master.
This might be problematic, finding someone with both skills sets would definitely be challenging, so the Romach approach might be a more practical solution. Time and research will help to determine the viability of different approaches.
These are by no means the only approaches to consider, just some initial conjecture and discussion.