The monograph examines the issue of self-harm in adolescents, a high-risk behavior in which individuals intentionally cause themselves harm. Research in this area has produced significant disparities, with experts disagreeing on the definition and methods for identifying self-harm. The specifics of its occurrence, signs, risk and protective factors, and dynamics of development or prognosis are all unclear. The monograph aims to provide basic information on self-harm, its prevalence, and forms, as well as to clarify its formation and retention as a maladaptive coping strategy. Furthermore, it presents unique data from a multi-year research project on a group of adolescents and identifies potential areas for further research.