Hi Dan
An annulment can only be issued in the case of the marriage not having been consummated, however if you was the one with the phyco problems and you kept it hidden from her, then this may well be accepted, especialy if you kept a hidden drug use or criminal past, but it would have to be your partner who wishes to accept your divorce, if she is still under immigration restrictions, this might not affect her stability.
If it was your partner who hid the truth it could be accepted as you didn't know and it may affect her immigration outcome.
Anyone who is legaly divorced and has the usual document showing peddiment is allowed to marry.ecause of grounds of phycological problems.
Information below will give you more information on annulments.
http://en.wikipedia.org/wiki/Annulme..._for_annulment
To be hoest, its unlikely the embassy will know if your marriage ended because of phycological problems.
A very good solicitor below will help
Arani and Co Solicitors
43A South Road
Southall
Middlesex
0208 8935000