The development of Non-Suicidal Self-Injury (NSSI) during adolescence: A systematic review and Bayesian meta-analysis.

BACKGROUND: Despite a surge in research on self-injury in the last decade, a summary of research findings about the development of Non-Suicidal Self-Injury (NSSI) over time in community youth samples is not yet present in the scientific literature. This study aims to summarize the empirical literature on this topic, examining both the occurrence (Study 1) and frequency (Study 2) of NSSI over time, and for this reason, a Systematic Review and Bayesian Meta-Analysis were conducted. METHODS: Following the PRISMA guidelines, the longitudinal studies included in the systematic review consisted of 41 papers (Study 1 = 16; Study 2 = 25). Only studies with available data were included in the meta-analysis (Study 1 = 12; Study 2 = 11). RESULTS: First, the findings highlight limits related to methodological aspects, the design of the studies, and the availability of data. Meta-analytic results shows that across development, the frequency (i.e., not the occurrence) of NSSI increases for the group of younger adolescents, remains stable in the group of middle adolescents, and it decreases for older adolescents. LIMITATIONS: This study highlights some limitations that can be summarized in three different macro categories: the first refers to methodological aspects (e.g., the lifetime prevalence of NSSI), the second to the design of the studies (e.g., not homogeneous cohort; short-term covered), and the third to the availability of data. CONCLUSIONS: The current meta-analysis tries to shed light on the longitudinal research on NSSI behavior and how this behavior develops in terms of both occurrence and frequency, providing practical and methodological indications for future research.

Exposure to and Speaking Up Against Online Ethnic Hate Speech: The Role of Xenophobia in a Three-Wave Longitudinal Study.

Nowadays, adolescents have extensive access to Information and Communication Technologies, which allow them to engage in social networking activities that may expose them to Online Hate Speech (OHS). While there are few cross-sectional studies about the effects of OHS Exposure on attitudes and aggressive behavior, no study aims to analyze the tendency to Speak Up when exposed to certain content (e.g., reporting, etc.). In addition, no instruments have yet been validated to assess these constructs. The aim of the present study, focused on Online ethnic Hate Speech (OeHS), is double: (a) develop a scale to measure OeHS Exposure and the tendency to Speak Up and analyze its psychometric properties; (b) analyze the longitudinal association between Xenophobia (XEN), OeHS Exposure, and Speaking Up against OeHS, while taking into account gender differences and the nested nature of the data. Six hundred sixty-six Italian high school students (52.7 percent male; MAge = 15[0.64]), nested in 36 ninth grade classes (10 schools), took part in the longitudinal study. The first wave of data collection occurred in early 2020, before the COVID-19 pandemic. The second and third waves took place 12 and 15 months later, respectively. Findings suggest that the OeHS Scale has good psychometric properties. Moreover, according to the findings, while the three variables of interest are always cross-sectionally correlated, a longitudinal negative association have been found between XEN and both Exposure and Speaking Up. Regarding the impact of OeHS Exposure, the good news is related to the absence of a longitudinal association with both XEN and Speaking Up.

Peer victimization and developmental psychopathology in childhood and adolescence Italian psychiatric emergency unit. A single center retrospective observational study.

Peer victimization is a public health concern that affects a significant proportion of children and adolescents. The study evaluated the prevalence of peer victimization among 440 subjects referred to Emergency Department for a psychiatric consultation and analyzed the association with psychopathological symptoms. Sample was divided into two categories (6-13 and 14-18 years old). Logistics regression analysis was performed. Peer victimized were reported in 16.3% of subjects; 27.7% were younger than13 years old and 72.3% were between 14-18 years old, representing the main targets for peer victimization.A significant association was found between being peer victimized and depressive disorder (OR=4.57) in subjects younger than 13 years old and, with post-traumatic stress disorder (PTSD)(OR=6.52) in subjects older than 13 years old. Furthermore, linkage between being peer victimized and obsessive-compulsive disorder (OCD)(OR=4.45) was noted. Increased frequency of repeated hospitalizations was also documented.This is the first Italian study about children and adolescent peer victimization in psychiatric setting, showing a significant higher risk for depressive disorder in subjects younger than 13 years old and PTSD and OCD in subjects older than 13 years old. Investigating experiences of peer victimization provides an early diagnosis and a more efficient treatment plans, guaranteeing an improved clinical outcome.

Non-Suicidal Self-Injury in Adolescence: The Role of Pre-Existing Vulnerabilities and COVID-19-Related Stress.

For many adolescents, the COVID-19 pandemic represents a uniquely challenging period, and concerns have been raised about whether COVID-19-related stress may increase the risk for self-injurious behaviors among adolescents. This study examined the impact of pre-existing vulnerabilities on the occurrence and frequency of Non-Suicidal Self-Injury (NSSI) through COVID-19-related stress, and whether the impact of COVID-19-related stress on NSSI was buffered by the perceived social support during the pandemic. Participants were 1061 adolescents (52.40% females; Mage = 15.49 years, SD = 0.76) from a two-wave longitudinal study, which included assessments before the COVID-19 onset and one year later the declaration of the pandemic. Path analyses showed that adolescents with a prior history of NSSI, higher levels of internalizing symptoms, and poor regulatory emotional self-efficacy before the COVID-19 pandemic reported higher levels of COVID-19-related stress which in turn increased their risk to engage in NSSI. Besides, the findings did not support the role of social support as a moderator of the association between COVID-19 related stress and the occurrence/frequency of NSSI. These findings suggest that enhanced stress perception may serve as a key pathway for the continuation and development of NSSI among vulnerable adolescents facing adverse life events.

Pathways to resilience: The parallel change in children's emotional difficulties and family context during the COVID-19 lockdown in Italy.

OBJECTIVE: The study analyses which pathways to adjustment emerged at the family level during the COVID-19 containment period in Italy, during which children were locked down with their families for 56 days from March 11 to May 6. Using a longitudinal design, with data pre- and postevent, a bivariate latent change score model analyzed the covariance of the change in family well-being (FW) and in emotional difficulties (ED), testing if the longitudinal change in ED is a function of the starting level of FW, and vice-versa. Children's stress reactions to the pandemic and other related experiences were included as additional predictors. METHOD: A total of 166 middle school students (86 females) with a mean age of 11.14 (SD = .47) completed two online questionnaires, in January 2020 (T0) and in June 2020 (T1). RESULTS: Results showed that children's ED decreased significantly, on average, during the lockdown period, and FW remained constant. ED and FW change scores had a significant and negative covariation (ß = - .46; p = .01). When family well-being increased emotional difficulties decreased, and vice versa. FW at T0 predicted no change in FW, nor did T0 scores of ED predict any change in FW. CONCLUSIONS: The strong intercorrelated change between children's ED and FW during the lockdown does not seem influenced by preexisting levels of individual and family functioning. Findings supported the view that for some families, the COVID-19 lockdown was also an opportunity to experience deeper emotional connections, contributing to a decrease in ED. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Reciprocal associations between peer problems and non-suicidal self-injury throughout adolescence.

BACKGROUND: Peer problems have emerged as important predictors of Non-Suicidal Self-Injury (NSSI) development during adolescence. However, the possibility that adolescents who engage in NSSI may, in turn, be at increased risk for experiencing difficulties with their peers has rarely been examined. This study investigated the reciprocal associations between peer problems (e.g. peer victimization, friendship stress and loneliness) and NSSI throughout adolescence, distinguishing between- and within-person effects. METHOD: Participants were 866 adolescents (54.5% females; Mage = 13.12 years, SD = 0.78), who took part in six waves of data collection. Adolescents completed self-report measures of NSSI, friendship stress and loneliness and they took part in a peer nomination procedure to assess peer victimization. Random Intercept Cross-Lagged Panel Models (RI-CLPMs) were used to estimate within-person cross-lagged effects between each peer problem and NSSI from Grade 7 to 12. RESULTS: After accounting for between-person associations between peer problems and NSSI, results indicated that higher-than-usual levels of NSSI predicted higher-than-usual levels of adolescents' own friendship stress, loneliness and peer victimization at the subsequent time point. Yet, sensitivity analyses revealed that most of these effects were strongly attenuated and explained by within-person fluctuations in depressive symptoms. No within-person cross-lagged effects from peer problems to NSSI were found. CONCLUSIONS: Findings highlight that the associations between peer problems (i.e. friendship stress, loneliness) and NSSI may be largely explained by shared underlying factors; yet, some evidence also suggests that NSSI engagement may increase adolescents' risk to experience difficulties in the relationships with their peers, in part via increases in depressive symptoms.

Teachers' Responses to Bullying Questionnaire: A Validation Study in Two Educational Contexts.

Given the high prevalence and dramatic impact of being bullied at school, it is crucial to get more insight into how teachers can reduce bullying. So far, few instruments have measured elementary teachers' responses to bullying. This study investigated the validity of the student-reported Teachers' Responses to Bullying Questionnaire. The factor structure and measurement invariance were tested across two educational contexts among fourth and fifth grade students from Italy (n = 235) and Belgium (n = 667). Furthermore, associations between student-perceived teachers' responses and students' bullying behavior were examined. Confirmatory Factor Analysis supported the predicted five-factor structure, distinguishing Non-Intervention, Disciplinary Methods, Group Discussion, Mediation, and Victim Support. A partial factor means invariance model was found, allowing for valid comparisons between the Italian and Belgian educational contexts. Significant associations were found between self-reported, but not peer-nominated, bullying behavior and most student-perceived teachers' responses.

The effect of the NoTrap! Antibullying program on ethnic victimization: When the peer educators' immigrant status matters.

Nowadays, an increasing number of children and adolescents living in Europe have an immigrant background. Because ethnicity is a recognizable characteristic that may become the driver of bullying, these youths are at high risk of victimization. School interventions based on peer-led approaches, assuming all the conditions postulated in contact theory, could be suitable to counteract bias-based bullying and victimization.This study aims to analyze whether the NoTrap! antibullying program, an evidence-based peer-led intervention, may also be effective in counteracting ethnic bullying and victimization when students with an immigrant background are involved as peer educators. There were 1,570 students who participated in the study: 24 control classes (N = 476) and 50 experimental classes (N = 1094). Within the last group we identified two conditions: 30 classes in which all peer educators were Italian (Experimental A, N = 661); 20 classes in which at least one of them had an immigrant background (Experimental B, N = 433). Results of two linear mixed models showed a significant interaction Time × Experimental condition for ethnic victimization, F(1, 1170) = 4.185; p = .015. Specifically, the NoTrap! is effective in reducing ethnic victimization when at least one student with an immigrant background is involved as a peer educator. Only in this condition, indeed, peer educators are directly involved in the phenomenon they counteract, and all four circumstances postulated in the contact theory are satisfied. No effects on ethnic bullying have been found, F(1, 1162) = .215; p = .806. This is in line with the activities proposed in the program, which is more focused on empowering victims than on acting directly on bullies. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

The longitudinal association between loneliness and depressive symptoms in the elderly: a systematic review.

OBJECTIVE: Loneliness and the onset of depression in old age are growing problems related to the greater life expectancy nowadays. This review investigated the longitudinal association between loneliness and depressive symptoms in the elderly. DESIGN: A comprehensive search was conducted using three databases (Scopus, PsycInfo, and PubMed) combing for empirical studies published up until July 2020. A total of 4.549 abstracts and 221 full-text articles were assessed. Three authors independently reviewed titles and abstracts; disagreements were resolved by consensus. RESULTS: Ten studies were included in the final review. We identified two categories of studies based on the outcome considered in each article: 1) the longitudinal effect of loneliness on depressive symptoms and 2) the clinical course of depression and its association with loneliness. All the articles reported a significant and positive association between loneliness and depressive symptoms in their longitudinal design research, ranging from an odds ratio of 0.41 to 17.76. The heterogeneity regarding the effect size in the analyses can be explained by the multifactorial design implemented by most of the studies included. CONCLUSIONS: Future research should investigate the moderators' role and how it may influence the longitudinal association between loneliness and depression over the years.

Victimization among children and adolescents accessing the Meyer pediatric hospital: A retrospective study.

PROBLEM: The consistent prevalence and occasionally severe consequences of bullying and victimization suggest the need to include a more accurate assessment of these episodes within the Emergency Departments (ED). However, the literature on mental health related symptoms of bullying/victimization treated in the ED is still scarce. The aim of this study is to assess the prevalence of peer victimization amongst children and adolescents referred to an Italian Pediatric Emergency Department. Differences between Hospital Departments, type of victimization and ages are tested. METHODS: A retrospective observational study was conducted with 705 subjects. The age range was from 6 to 18 years old (M = 13.09; SD = 3.048). FINDINGS: 15.3% of the sample reported to be victimized (8.2% occasionally; 7.1% systematically). For the Child and Adolescent Psychiatry Unit, we found a significant association between peer victimization and being adolescent (Fisher's p = 0.003). In addition, a significant association was found between verbal victimization and Child and Adolescent Psychiatry Unit (Fisher's p = 0.02) and physical victimization and Child Abuse Department (Fisher's p < 0.001). CONCLUSION: Findings suggest the importance of an accurate assessment of victimization experiences of children and adolescents with access to ED, to prevent future re-victimization and crystallization of symptoms across time.

Development and Validation of the Ethnic Moral Disengagement Scale.

Research has underlined that moral disengagement processes, by which people switch off their moral values and act aggressively without experiencing guilt, are highly connected with contextual factors. However, research on situational variations in moral disengagement is limited, especially considering the associations with characteristics such as the ethnic origin of potential victims. The general aim of the present study was to develop a brief, specific measure of ethnic moral disengagement able to catch individual justification used in the case of ethnic bullying and cyberbullying, and test its validity and reliability. An eight items scale was developed and administered in study 1, in a sample of 961students attending several Italian high schools (53.5% female; Mage 15 years). Considering the results of the CFA, we modified one of the items and the scale was administered again, in a second sample of 1,229 students (49.9% female; Mage 15.62 years) in study 2. A one-factor model of ethnic moral disengagement fit the data well and internal consistency showed to be good. As an additional step, we found that the model was invariant across Italian adolescents and youths with a different ethnic or culture of origin (having at least one parent born abroad) strengthened our confidence regarding the factorial integrity of the scale. Last, the scale showed to be positively associated with ethnic bullying and cyberbullying. Generally, findings suggested that the Ethnic Moral Disengagement scale can be a useful tool for those interested in measuring moral disengagement and evaluating how it impacts bullying and cyberbullying of minority groups.

Positive and Negative Experiences of Living in COVID-19 Pandemic: Analysis of Italian Adolescents' Narratives.

INTRODUCTION: Despite a growing interest in the field, scarce narrative studies have delved into adolescents' psychological experiences related to global emergencies caused by infective diseases. The present study aims to investigate adolescents' narratives on positive and negative experiences related to COVID-19. METHODS: Italian adolescents, 2,758 (females = 74.8%, mean age = 16.64, SD = 1.43), completed two narrative tasks on their most negative and positive experiences during the COVID-19 emergency. Data were analyzed by modeling an analysis of emergent themes. RESULTS: "Staying home as a limitation of autonomy," "School as an educational, not relational environment," the impact of a "new life routine," and experiencing "anguish and loss" are the four emergent themes for negative experiences. As for positive experiences, the four themes were "Being part of an extraordinary experience," "Discovering oneself," "Re-discovering family," and "Sharing life at a distance." CONCLUSION: Authors discuss the impact of COVID-19 on adolescents' developmental tasks, such as identity processes and autonomy acquisition.

Mapping community, social, and economic risks to investigate the association with school violence and bullying in Italy.

BACKGROUND: School violence and bullying are a pandemic issue. The academic literature underlined the need to investigate social-contextual risk factors. The United Nations called for more comprehensive and disaggregated data to inform prevention strategies. OBJECTIVE: The present study comprises a set of secondary analyses on Italian data from the International Civic and Citizenship Study 2016. We adopted an innovative 'bottom-up' approach to identify the level of disaggregation for national data. The researchers focused on community, social, and economic risk indicators at school-level, and investigated whether it was possible to aggregate schools in different classes, depending on their risk profile. PARTICIPANTS AND SETTINGS: Analyses were implemented on a nationally representative sample of 170 Principals of lower secondary schools, 2,527 teachers and 3,766 students at grade 8. METHODS AND ANALYSES: A Latent Class Analyses was conducted on risk indicators and four classes of risk were identified: No Risk, Community Risk, Socio-economic Risk, Multi-Risk (entropy = .786). No significant differences were found across classes in relation to urban/rural location, school size, and geographical macro-partition. On the contrary, significant differences emerged when considering teachers' perception of bullying, social problem, and students' behavior at school. Furthermore significant differences were found for the quality of relationship with teachers as reported by students. CONCLUSIONS: Results a) suggested a potential gradient of increasing risk moving across the classes; b) provided a contribution to address the gap in the investigation of contextual factors and bullying; c) offered a new lens to tailor interventions to prevent school violence and bullying.

Ethnic Bullying Victimization in Italy: The Role of Acculturation Orientation for Ethnic Minority Adolescents With Differing Citizenship Statuses.

This study examines the role of acculturation orientation toward home and host countries in ethnic bullying victimization, by considering citizenship status and taking into account social withdrawal. Within a larger school project with middle and high school students, we analyzed data on 252 adolescents from immigrant backgrounds: 71 born abroad without Italian citizenship (Males = 71.4%; mean age = 13.98, SD = 1.7); 96 born in Italy to immigrant parents and without Italian citizenship (Males = 58.3%; mean age = 13.26, SD = 1.6); and 85 Italian citizens born in Italy with an immigrant parent (Males = 54.7%; mean age = 13.12, SD = 1.5). At the univariate level we found that the group of adolescents born abroad with foreign parents showed significantly higher levels of ethnic victimization compared to the group of adolescents born in Italy with an Italian parent. The latter also reported a significantly higher mean in Acculturation Orientation toward their Host Country (i.e., Italy) compared to the other two groups. Looking at the processes working within each group, we found differences in the patterns of association between acculturation orientation and ethnic bullying victimization. Specifically, we found a significant and positive association between acculturation orientation toward the home country and ethnic victimization in the two groups of adolescents born in Italy, while acculturation orientation toward the host country seems to be a protective factor only for adolescents with Italian citizenship. Acculturation orientation does not play any role in ethnic victimization for the first generation of immigrants, while for this group we found a stronger positive effect of Social Withdrawal. Citizenship status appears to be a good indicator of belonging to an ethnic minority group with a background of immigration: it seems to catch specific processes in ethnic bullying victimization.

Voluntary Vs Nominated Peer Educators: a Randomized Trial within the NoTrap! Anti-Bullying Program.

There is a debate in scientific literature about the effectiveness of a peer-led approach to anti-bullying interventions. In order to understand which circumstances and for whom these approaches work best, the present study was carried out within the NoTrap! anti-bullying program. Using a cluster design, classes were randomly assigned into two different peer educator recruitment strategies: volunteering (N = 500; 48% females; mean age = 13.5 years, ds = 1.3) vs peer nominated (N = 466; 38% females; mean age = 13.9 years, ds = 1.3). Results showed that voluntary peer educators suffered a higher level of victimization, while the nominated ones tended to be more popular and likable. Furthermore, a set of linear mixed-effect models showed that the program was effective in reducing bullying and victimization, and in increasing defending behaviour only in the voluntary recruitment condition. On the contrary, in classrooms under the peer nominated recruitment condition, bullying and victimization remained stable, and defending behaviour increased only for peer educators, but not for their classmates. This implies that the step of peer selection and recruitment must be kept into consideration in developing and validating an intervention, because of its possible impact on the effectiveness of the whole intervention.

Distinguishing spontaneous from deliberate mind wandering in adolescents: The role of attentional control and depressive symptoms.

Research on individual differences in mind wandering (MW) in healthy adults has supported the separation of spontaneous and deliberate MW given their different association with a number of psychological traits. This study aimed to further test this distinction by investigating the associations of the two types of MW with attentional control and depressive symptomatology in adolescents. Data were collected on 439 9-10th graders, who completed measures of spontaneous and deliberate MW, distractibility, difficulty in attentional shifting, and depressive symptomatology. A multivariate three-level multiple regression revealed that distractibility was a significant predictor of only spontaneous MW, whereas difficulties in attentional shifting and depressive symptoms were significant predictors of both types of MW. However, the last two variables were stronger predictors for spontaneous than for deliberate MW. These findings provide support for the distinction, beyond their theoretical and empirical overlap, between the two types of MW also in adolescents and suggest the independent contribution of cognitive functioning and depressive symptoms. Statement of contribution What is already known? Studies on mind wandering (MW) in adults have shown that spontaneous and deliberate MW reflect dissociable cognitive experiences. In adults, trait-level tendency to spontaneous MW seems to reflect difficulties in controlled attentional processing. The majority of studies on MW in adolescents have treated this phenomenon as unitary and found a relation with negative affect, stress, and self-esteem. What does this study add? This is the first study to examine cognitive functioning and depressive symptoms as correlates of spontaneous and deliberate MW in adolescents. We found that distractibility is a significant predictor of only spontaneous MW. Difficulties in attentional shifting and depressive symptoms are significant predictors of both types of MW, although stronger for spontaneous MW. The findings support the distinction, beyond their theoretical and empirical overlap, between the two types of MW also in adolescents and call for future studies on the function of deliberate and spontaneous MW across development.

The Teacher's Role in Preventing Bullying.

The teacher plays an important role in the management of classroom bullying (Yoon and Bauman, 2014). Therefore, understanding and fostering teachers' characteristics able to predict successful responses to bullying and victimization is a priority for prevention programs. The aim of this study was to evaluate whether the association between the teacher's individual characteristics, such as her/his competence in regard to the phenomenon, job satisfaction, and self-efficacy, and the school level of bullying/victimization was mediated by the teacher's intervention when an episode of bullying occurred. The study included 120 teachers (17.5% boys; 79.2% girls), between the ages of 25 and 66 (mean age = 48.21; SD = 9.22), and 1,056 students (40.3% boys; 59.6% girls), between the ages of 11 and 17 (mean age = 13.09; SD = 1.46). A total of 57% of the students were attending secondary middle school and 42.2% were in secondary high school. Path analyses showed that for perpetrated behaviors, teachers' competence on bullying affects students report of bullying through a higher likelihood of teachers' intervention after a bullying episode occurred. The indirect effect resulted significant. Lower levels of bullying and victimization were associated with teacher job satisfaction, thus indicating how professional fulfillment can influence the classroom climate. The model for victimization was the same, except that the indirect path was not significant. Findings are discussed in terms of teachers' involvement in bullying intervention and prevention.

How to Stop Victims' Suffering? Indirect Effects of an Anti-Bullying Program on Internalizing Symptoms.

Victims of bullying and cyberbullying present internalizing problems, such as anxiety, psychosomatic and depressive symptoms, and are at higher risk of considering or attempting suicide. Researchers have put great effort into developing interventions able to stop bullying and cyberbullying, and thus buffering possible negative consequences. Despite this, only a few of them have investigated the effects of these programs on the psychological suffering of the victims. The NoTrap! program is an Italian evidence-based intervention able to reduce victimization, bullying, cybervictimization and cyberbullying. The aim of the present study is to analyze whether the NoTrap! program can reduce internalizing symptoms through the decrease in both victimization and cybervictimization. Participants were 622 adolescents, enrolled in the 9th grade of eight high schools in Tuscany (experimental group: N = 451; control group: N = 171). We collected data at three time points: pre-, mid- and post-intervention. Using latent growth curve models, we found that the program significantly predicted the change in internalizing symptoms over time. Furthermore, the mediation model showed that only the indirect effect via cybervictimization was significant. In summary, the program reduced internalizing symptoms within the experimental group successfully, through the decrease in cybervictimization more so than through the mediational effect of decreasing victimization.

The Efficacy of the "Dat-e Adolescence" Prevention Program in the Reduction of Dating Violence and Bullying.

Background: The aim of this study was to assess the efficacy of the school-based "Dat-e Adolescence" prevention program in the reduction of dating aggression and victimization and bullying in adolescents. Method: a RCT design with three waves (pre-test, post-test and follow-up six months apart) and two groups (an experimental group and a control group) were used. One thousand four hundred and twenty three (1423) adolescents, mean age 14.98 (557 in the experimental group) participated in the study. Results: Efficacy evaluation was analyzed using Multiple-group latent growth models and showed that the Dat-e Adolescence program was effective in reducing sexual and severe physical dating violence and bullying victimization. Conclusions: The results suggest that dating violence prevention programs could be an effective approach for tackling different behavioral problems in adolescence given the protective and risk factors shared between dating violence and bullying.

For Whom Is Anti-Bullying Intervention Most Effective? The Role of Temperament.

Studying moderators of the effects of anti-bullying universal interventions is essential to elucidate what works for whom and to tailor more intensive, selective, and indicated programs which meet the needs of non-responders. The present study investigated whether early adolescents' temperament-effortful control (EC), negative emotionality (NE), and positive emotionality (PE)-moderates the effects of the KiVa anti-bullying program. The sample consisted of 13 schools, with 1051 sixth-grade early adolescents (mean age = 10.93; SD = 0.501), randomly assigned to the KiVa intervention (seven schools; n = 536) or to the control condition (six schools; n = 516). Adolescents reported bullying and victimization before the intervention (pre-test) and after (post-test). Temperament was assessed by a self-report pre-test. Findings showed that EC and NE moderated intervention effects on bullying, indicating that subgroups with high levels of EC, and with low and medium levels of NE were those who benefited most from the intervention. The low-EC subgroup showed a lower increase compared to the control condition, with a considerable effect size. Conversely, the high-NE subgroup did not show any positive effects compared to the control group. Regarding victimization, findings showed that early adolescents with high and medium levels of PE were the subgroups who benefited the most from the intervention, whereas the low-PE subgroup was the most resistant. The present study confirms the relevance of considering temperament as a moderator of intervention effects, since interventions tailored to early adolescents with specific traits might yield larger effects.