Have you heard of "cutting"? If you're a parent, you'd better read up. "Cutting" refers to self-mutilation – using knives, razor blades or even safety pins to deliberately harm one's own body – and it's spreading to a school near you. Actresses Angelina Jolie and Christina Ricci did it. So did Courtney Love and the late Princess Diana. On the Internet, there are scores of websites (with titles such as "Blood Red," "Razor Blade Kisses" and "The Cutting World") featuring "famous self-injurers," photos of teenagers' self-inflicted wounds and descriptions of their techniques. The destructive practice has been depicted in films...