Sheyla Hershey most likely has something called body dysmorphic disorder. Simply, what she really looks like and what she sees in the mirror are not the same thing for her. So, in order to chase the ideal of what she thinks she should look like, she undergoes dangerous surgeries for no medical benefit. It's similar to how anorexics or bulimics look at themselves. When they look in the mirror they always think they're fat. When Sheyla Hershey looks in the mirror she probably feels she's small-chested even though her breasts are some of the largest on record. It's a sad disorder.

The woman who had all the plastic surgeries in order to look like Barbie is another prime candidate for this disorder. The reason it's classed as a disorder is because these people are risking their lives, and are having negative consequences in their life because of their need to chase what they believe is their "ideal body."

Sheyla Hershey broke up with her boyfriend when he said he couldn't support yet another breast surgery on her already massive chest. I would say that qualifies as a negative consequence from an interpersonal standpoint.