An investigation of why so many people deliberately hurt themselves and what can be done to help them. The illness "outed" on a global scale when Princess Diana admitted hurting herself deliberately, and continues to be practised mainly by middle-class women who start in their teens and self-harm throughout their lives. Most cutters are women who have been emotionally, sexually or physically abused as children, but Marilee Strong's research shows that self-mutilation also appears in other groups. There are powerful first-person stories, in which cutters describe their ritualistic methods and somewhat addictive cravings for seeing their own blood. Though research is in its infancy, therapists say there are now promising treatments - from medication to intensive psychotherapy - for the millions of "cutters". Strong reveals what the afflicted and those close to them can do to start a process of healing.