According to wikipedia, Tourette syndrom is "an inherited neuropsychiatric disorder with onset in childhood, characterized by the presence of multiple physical (motor) tics and at least one vocal (phonic) tic; these tics characteristically wax and wane" and "Tourette's was once considered a rare and bizarre syndrome, most often associated with the exclamation of obscene words or socially inappropriate and derogatory remarks (coprolalia)."
So I guess I can safely describe those who cannot control but to blurt out their Christian faith randomly and inappropriately (mid conversation with nothing to do with religion and sometimes to total strangers) as sufferer of what I'd call "Christian Tourette."
Okay, maybe it's not exactly Tourette, maybe it's just a "vocal (phonic) tic," unless you count the inability to stop butting into other people's business as a physical (motor) tic.
My friend who had lived in Illinois told me that to be consider having truth faith, you must acquire the ability to constantly remind others of your faith. Now the mystery of why AND how have finally been solved.