Pimply Stress

This mini-article on acne and anxiety raises a combo platter of questions relevant to what we're going over in class.

1) Reverse cause & effect: Does acne cause stress, or does stress cause acne?
2) Questionable statistics: Do you trust the stat that students were 23 percent more likely to experience breakouts around the time of a test? Is it a good study? A reliable source? An undemanding stat?
3) Questionable use of statistics: If the above statistic is true, is it reasonable to conclude that anxiety causes acne? Or is there another plausible explanation?

What say you?