" Adolescence is also a time when aggressive and other nonsexual drives intensify, which may play a role in the emergence of cutting. "There is something about that developmental phase, the biochemical changes that are occurring, that starts to activate all the structural damage in the brain that came from earlier trauma," says Mark Schwartz. It is at this age that abused children start exhibiting a number of acting-out and acting-in behaviors, from cutting and eating disorders to acts of outward aggression. Schwartz believes it isn't hormones alone that are responsible for this sudden upsurge in impulsive behavior but a complex interaction of the brain, the hormones, and the social environment. "

― Marilee Strong , A Bright Red Scream: Self-Mutilation and the Language of Pain