I think it's hard to say anything concrete about any group of people, there are always circumstances that makes one story different from another but in general I agree with the overall thought and agree, post-adoption, we could all use some support!
IMHO one of the biggest difference is that in a typical closed adoption the birthparents never know if the children are dead or alive, so when the adoption occurs some often grieve as though the child hass passed away. Where as in some modern day open adoption birthparents may either have visits or photos so at least they know the kids are alive....and if they have visits these parents also have the chance to meet their children or even be a part of their lives...but I'm sure that too has it's own issues.
I do however subscribe to the thinking that were are all the same, we are all human beings, we all hurt, love and yearn for support just like anyone else does
C.