Update: well worth reading the comments below by bourach, who blogs at http://conversationswithmyhead.blogspot.com/, on their experience of personality disorder, and of what aspects of church life and community they find helpful.
Thought-provoking piece by the BBC's Mark Easton from a few days ago, looking at the effects of personality disorders, and the moral questions they raise.
We don't know. Research is thin. And there are some who argue that doctors' attempts to find a therapeutic label for it are in danger of simply medicalising bad behaviour.
...But the dilemma remains. Not every trauma victim goes on to abuse. Not every neglected child self-harms. Society cannot easily forgive or excuse those that commit appalling crimes on the basis that it is a consequence of a troubled past.
The question is still unanswered. Where does personality end and disorder begin?
It's quite a long piece, but raises all sorts of issues: when is a diagnosis an explanation, and when is it an excuse? What's the effect of culture: we've become a society which is much happier about giving free reign to self-expression, but do we have the self-control to know when this is appropriate and when it isn't?
When we did the Myers-Briggs personality test at training college, one wag at the college revue coined the line 'it's not a sin, it's just my personality'. God has given us life to richly enjoy, and to live to the full, but living life to the full isn't the same as self-indulgence, and I wonder if those two ideas have become confused somewhere along the line. Jesus teaches that the two are mutually opposed.
But you can only give your life away if it's yours to give, so if a personality disorder means that you're not fully in control of your life in the first place......I'd better stop there......