Physiological markers for cutting, other self-harming behaviors by teenage girls found

on-fatal, self-inflicted injuries by adolescent and young adult females are major public health problems and researchers have found physiological evidence that this behavior may lead to a more serious psychological condition called borderline personality disorder.

University of Washington psychologists have discovered that adolescent girls who engage in behaviors such as cutting themselves have lower levels of serotonin, a hormone and brain chemical, in their blood. They also have reduced levels in the parasympathetic nervous system of what is called respiratory sinus arrhythmia, a measure of the ebb and flow of heart rate along with breathing.