Bullying is a common and significant risk factor for mental and physical health problems. The aim of the outlined study was to evaluate the German version of the Olweus Bullying Prevention Program (OBPP) and to investigate potential moderators of its effectiveness. 23 schools started with the implementation and all students were invited to complete the Olweus Bullying Questionnaire annually. For our analyses, the data from grades 5 to 9 were used (t0: n = 5759; t1: n = 5416; t2: n = 4894). 16 out of the 23 schools completed the 18-months implementation period. The effectiveness of the program statistically depended on its complete implementation (χ2(2) = 7.62, p = 0.022). In the group of non-completers, the prevalence of victimization did not change during the observation period of 2 years (χ2(2) = 4.64, p = 0.099). In the group of the completer schools, a significant decrease in bullying between t0 and t1 was found for victims (t0: 9.14%; t1: 6.87%; OR = 0.74; 95% CI 0.62–0.88; p = 0.001) and perpetrators (t0: 6.16%; t1: 4.42%; OR = 0.70; 95% CI 0.55–0.89; p = 0.004). After 24 months (t2), this decrease could be retained (victims: t2: 6.83%; OR = 0.73; 95%CI = 0.61–0.88; p = 0.001; perpetrators: t2: 4.63%; OR = 0.72; 95% CI 0.57–0.92; p = 0.009). Furthermore, we found the following moderators of program effectiveness in the completer schools: (1) gender (with a stronger decrease among victimized girls; p = 0.004) and (2) school grade (with a stronger decrease of victimization among grades 5–7; p = 0.028). The German version of the OBPP significantly reduced the bullying prevalence in the completer schools. Effective prevention needs time and resources: fulfilling the 18-months implementation period was the basis for positive results.

BackgroundThe aim of this study was to investigate whether bullying among students is associated with symptoms of posttraumatic stress disorder (PTSD), and whether associations are comparable to other traumatic events leading to PTSD.MethodsData were collected from 219 German children and adolescents: 150 students from grade six to ten and 69 patients from an outpatient clinic for PTSD as a comparison group. Symptoms of PTSD were assessed using the Children’s Revised Impact of Event Scale (CRIES) and the Posttraumatic Symptom Scale (PTSS-10). A 2 × 5 factorial analysis of variance (ANOVA) with the factors gender (male, female) and group (control, conflict, moderate bullying, severe bullying, traumatized) was used to test for significant differences in reported PTSD symptoms.ResultsResults showed that 69 (46.0%) students from the school sample had experienced bullying, 43 (28.7%) in a moderate and 26 (17.3%) in a severe way. About 50% of the severe bullying group reached the critical cut-off point for suspected PTSD. While the scores for symptoms of PTSD were significantly higher in bullied versus non-bullied students, no significant differences were found between patients from the PTSD clinic and students who experienced severe bullying.ConclusionsOur findings suggest that bullying at school is highly associated with symptoms of PTSD. Thus, prevention of bullying in school may reduce traumatic experiences and consequent PTSD development.