To the OP: don't under any circumstances declare this or any other 'fringe' ailment, especially if it isn't on your docs. At least it will clutter your career progress at worst it will destroy it before it starts.
My wife is a consultant psychologist with the NHS and she advises you have no legal requirement to declare something that is NOT on your records. Moreover - many of these posts offer sound advice. As far as ADHD is concerned - the jury is most definitely still OUT on this and several other misleading diagnosies.
