In both classificatory systems DSM-IV and ICD-10 self-injury is a symptom of borderline personality disorder (BPD). But it has been shown empirically that self-injury can also occur independent of BPD, for example, as a component of depressive states or even in adolescents without classifiable psychopathology. The scientific discussion about future diagnostic criteria recently led to a proposal to include Non-Suicidal Self-Injury as an independent disorder in the upcoming DSM-5 classification system. Based on recent epidemiological studies of adolescents in Germany, one may assume that approximately 4% of all youths in middle to late adolescence would fulfill the prevalence criterion (criterion A) of the proposed DSM-5 disorder (that is, at least five self-injury incidents within the previous 12 months). A precise classification of Non-Suicidal Self-Injury based on empirical research is needed to further the research, treatment, and prevention of this diagnosis.