***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Abstract Objectives : To establish the relation between recurrent peer victimisation and onset of  self reported symptoms of anxiety or depression in the early teen years . Design : Cohort study over two years . Setting : Secondary schools in Victoria , Australia . Participants : 2680 students surveyed twice in year 8 ( aged 13 years ) and once in year 9 . Main outcome measures : Self reported symptoms of anxiety or depression were assessed by using the computerised version of the revised clinical interview schedule .  Incident cases were students scoring ≥12 in year 9 but not previously . Prior victimisation was defined as having been bullied at either or both survey times in year 8 . Results : Prevalence of victimisation at the second survey point in year 8 was 51 % ( 95 % confidence interval 49 % to 54 % ) , and prevalence of self reported symptoms of anxiety or depression was 18 % ( 16 % to 20 % ) . The incidence of self reported symptoms of anxiety or depression in year 9 ( 7 % ) was significantly associated with victimisation reported either once ( odds ratio 1.94 , 1.1 to 3.3 ) or twice ( 2.30 , 1.2 to 4.3 ) in year 8 . After adjustment for availability of social relations and for sociodemographic factors , recurrent victimisation remained predictive of self reported symptoms of anxiety or depression for girls ( 2.60 , 1.2 to 5.5 ) but not for boys ( 1.36 , 0.6 to 3.0 ) . Newly reported victimisation in year 9 was not significantly associated with prior self report of symptoms of anxiety or depression ( 1.48 , 0.4 to 6.0 ) . Conclusion : A history of victimisation and poor social relationships predicts the onset of emotional problems in adolescents . Previous recurrent emotional problems are not significantly related to future victimisation . These findings have implication s for how seriously the occurrence of victimisation is treated and for the focus of interventions aim ed at addressing mental health issues in adolescents . What is already known on this topic Being bullied is a common experience for many young people Victimisation is related to depression and , to a lesser extent , anxiety , loneliness , and general self esteem Debate remains as to whether victimisation precedes the onset of emotional problems or whether young people with emotional problems “ invite ” victimisation What this study adds A history of victimisation predicts the onset of anxiety or depression , especially in adolescent girls Previous recurrent emotional problems are not significantly related to future victimisation Reduction in bullying in schools could have a substantial impact on the emotional wellbeing of young AIMS To examine the effects of the ' Healthy School and Drugs ' project , a Dutch school-based drug prevention project that was developed in the late 1980s and disseminated during the 1990s . This programme is currently being used by 64 - 73 % of Dutch secondary schools and it is estimated that at least 350000 high school students receive this intervention each year . DESIGN , SETTING AND PARTICIPANTS A quasi-experimental study in which students of nine experimental ( N = 1156 ) schools were compared with students of three control schools ( N = 774 ) . The groups were compared before the intervention , 1 year later , 2 years later and 3 years later . MEASUREMENTS Self-report measures of tobacco , alcohol and marijuana use , attitudes towards substance use , knowledge about substances and self-efficacy . FINDINGS Some effects on the use of tobacco , alcohol and cannabis were found . Two years after the intervention , significant effects could still be shown on alcohol use . Effects of the intervention were also found on knowledge , but there was no clear evidence for any effects on attitude towards substance use and on self-efficacy . CONCLUSIONS This study shows the Healthy School and Drugs project as implemented in Holl and may have some effect on drug use in the children exposed to it Summary of Etiological Analyses . T his analysis confirm ed the i m portance of school bonding to child devel-opm ent . V arious techniques w ere used to exam ine the rela-tionship betw een school bonding and positive and problembehavior , and these relationships w ere found during child-h o o d and ad o lescen ce . S chool b o n d in g in elem en taryschool w as related to initiation of drinking , sm oking , and alcohol abuse and dependence at age 2 1 . It also related tolow er likelihood of becom ing serious offenders in m iddleschool and joining a gang in adolescence . E lem entary and m iddle school bonding had a negative effect on violence inm iddle school through age 2 1 . It also reduced the chance ofschool m isbehavior , grade repetition , and dropout .  S choolbonding also affected positive developm ent . S chool bond-ing  w as associated w ith increases in academ ic achievem ent and social skills .  S chool bonding effects extended to high -risk groups including aggressive boys , children w ith parent sw ho m odeled problem behaviors , and children from low -incom e fam ilies .  S chool bonding in m iddle school w asrelated to desistance of serious delinquent behavior . T herelationship w as m aintained through age 2 1 , w ith studentsreporting greater school bonding in sevent h grade m orelikely to desist rather than escalate the seriousness of theiroffending . S chool bonding in m iddle school and the patternof bonding throughout m iddle and high school also relatedto reduced levels of substance use in 12th grade . T h u s , school bonding during elem entary and m iddle school w asconsistently related negatively to problem behaviors in thislongitudinal study .S everal com peting factors that m ight explain the rela-tionship betw een school bonding  and problem behaviorsw ere controlle d in the analyses , lending credibilit y to thepotential causal effect of school bonding . H ow ever , w hilenonexperim ental , longitudinal studies establish tim e order , they do not establish cause . A stronger criterion for estab-lishing the causal effect of school bonding com es fromintervention studies aim ed at changing the levels of schoolbonding and exam ining the effects on positive and problembehavior . S tatistically significant results of the preventionexperim ent em bedded w ithin S S D P are described below 
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Discussion We anticipate : finding a large number of studies missed by previous review s ; that non-intervention studies of school effects examine a greater breadth of determinants than are addressed by intervention studies ; and that intervention effect estimates are greater than for school-based health curriculum interventions without school-environment components