School violence includes violence between school students as well as attacks by students on school staff. It encompasses physical violence, including student-on-student fighting, corporal punishment; psychological violence such as verbal abuse, and sexual violence, including rape and sexual harassment. It includes many forms of bullying (including cyberbullying) and carrying weapons in school. It is widely believed by society to have become a serious problem in recent decades in many countries, especially where weapons such as guns or knives are involved. Forms of school violence and different types of bullying School violence is widespread. It occurs in all countries and affects a significant number of children and adolescents. It is mostly perpetrated by peers but, in some cases, is perpetrated by teachers and other school staff. School violence includes physical, psychological and sexual violence. Bullying Bullying is characterized by aggressive behavior that involves unwanted, negative actions, is repeated over time, and an imbalance of power or strength between the perpetrator or perpetrators and the victim. It is distinct from more common one-off conflicts among peers. Different types of bullying include physical, psychological, sexual, and cyber-bullying. Physical bullying includes repeated aggression such as being hit, hurt, kicked, pushed, shoved around or locked indoors, having things stolen, having personal belongings taken away or destroyed, or being forced to do things. It is different from other forms of physical violence such as physical fights and physical attacks. Psychological bullying includes verbal abuse, emotional abuse and social exclusion and refers to being called mean names, being teased in an unpleasant way, being left out of activities on purpose, excluded or completely ignored, and being the subject of lies or rumors. Sexual bullying refers to being made fun of with sexual jokes, comments or gestures. Cyber bullying includes being bullied by messages, i.e. someone sending mean instant messages, postings, emails and text messages or creating a website that makes fun of a student or by pictures, i.e. someone taking and posting online unflattering or inappropriate pictures of a student without permission; it also refers to being treated in a hurtful or nasty way by mobile phones (texts, calls, video clips) or online (email, instant messaging, social networking, chatrooms) and online hurtful behaviour. Physical fights According to the Global School-based Student Health Survey (GSSHS), a physical fight “occurs when two students of about the same strength or power choose to fight each other” and therefore is a