I think they have to be troubled and attractive. This is why they got Nicole Kidman to play Virginia Wolff. There are many, many, many unattractive women on the verge of a breakdown in our world, but we don't want to know from them. I really believe it is as simple as that. An attractive women torn and frayed allows to to leapfrog over the dog and pony show that Society demands you leap through the loops of to get to the prize (the pretty girl), because she isn't interest or is terrified of that structure and her part in it. More often than not she will gleefully allow you to take her to a private world of only you and she where you abuse her then comfort her in a kind of comforting cycled facsimilie of the buffetings of the society you both yearn to deny, both of you filling roles and sick desires and longings for eachother without the hassle of all those extra peoples and things. You are correct this has much to do with pornography.