Eep, youthful drug abuse! This is an interesting thought. I wonder how drugs affect magic? I wonder if drugs could be a gateway to Very Dangerous Magics? All I know is that he got mixed up with A Bad Crowd, and there might have been philosophy gone horribly wrong as a lure, and quite possibly something having to do with vampires, which is why the Society tagged him in the first place, and he worked with them for a while until something made him stop (disillusionment? unethical practises? he grew up and went "WAIT, WHAT?").

He could have been stationed in India, but then he might hate himself too much. :p OH GOD WHAT HAS OUR EMPIRE DONE WHY DON'T WE JUST LET THE VAMPIRES EAT US ALL.