Fuck everything else.
The Fewtrell Depersonalization Scale might be useful, too. There was a study where it seemed to achieve quite good properties. Unfortunately I wasn't able to find it anywhere. It seems to have been created for nothing. There have been no uses after the study of Lambert et al.
I thought about asking the Depersonalization Research Unit for it, but as they don't answer E-Mails I suppose this wouldn't work.
I have an idea: Will you go again to the Depersonalization Research Unit? If yes: Could you ask for the Fewtrell Depersonalization Scale? It would be useful if we had another acceptable questionare.