There is limited evidence that the school environment has a major influence on adolescent mental health, although student perceptions of teacher support and school connectedness are associated with better emotional health. More studies measuring school-level factors are needed. Randomized controlled trials evaluating 1 or 2 environmental components may have more success in establishing effective and feasible interventions compared with complex whole-school programs.

Background Rates of anxiety and depression are increasing among children and young people. Recent policies have focused on primary prevention of mental disorders in children and young people, with schools at the forefront of implementation. There is limited information for the comparative effectiveness of the multiple interventions available. MethodsWe did a systematic review and network meta-analysis, searching MEDLINE, Embase, PsycINFO, and Cochrane Central Register of Controlled trials for published and unpublished, passive and active-controlled randomised and quasi-randomised trials. We included educational setting-based, universal, or targeted interventions in which the primary aim was the prevention of anxiety and depression in children and young people aged 4-18 years. Primary outcomes were post-intervention self-report anxiety and depression, wellbeing, suicidal ideation, or selfharm. We assessed risk of bias following the Cochrane Handbook for Systematic Reviews of Interventions. We estimated standardised mean differences (SMD) using random effects network meta-analysis in a Bayesian framework. The study is registered with PROPSERO, number CRD42016048184.Findings 1512 full-text articles were independently screened for inclusion by two reviewers, from which 137 studies of 56 620 participants were included. 20 studies were assessed as being at low risk of bias for both random sequence generation and allocation concealment. There was weak evidence to suggest that cognitive behavioural interventions might reduce anxiety in primary and secondary settings. In universal secondary settings, mindfulness and relaxation-based interventions showed a reduction in anxiety symptoms relative to usual curriculum (SMD -0•65, 95% credible interval -1•14 to -0•19). There was a lack of evidence to support any one type of intervention being effective to prevent depression in universal or targeted primary or secondary settings. Comparison-adjusted funnel plots suggest the presence of small-study effects for the universal secondary anxiety analysis. Network meta-analysis was not feasible for wellbeing or suicidal ideation or self-harm outcomes, and results are reported narratively.Interpretation Considering unclear risk of bias and probable small study effects for anxiety, we conclude there is little evidence that educational setting-based interventions focused solely on the prevention of depression or anxiety are effective. Future research could consider multilevel, systems-based interventions as an alternative to the downstream interventions considered here.

Wellbeing is low and depressive symptoms high amongst teachers. Interventions aimed at improving their mental health might focus on reducing work related stress, and increasing the support available to them.

BackgroundSubstantial numbers of adolescents self-harm, but the majority of cases do not reach the attention of medical services, making community studies essential. The prevalence of suicidal thoughts and plans at this age, and the inter-relationships between suicidal thoughts, plans and self-harm remain largely unexplored.MethodCross-sectional analysis of self-reported questionnaire data collected from members of the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort, England. Respondents (n = 4810) were aged 16–17 years old and have been followed up since birth.ResultsAltogether 905 (18.8%) respondents had ever self-harmed. The prevalence of lifetime self-harm was higher in females (25.6%) than males (9.1%). The most commonly used method was self-cutting: this was used alone or in combination in 73.5% of episodes, compared to 10.0% who took overdoses alone or in combination with other methods. Of those who reported self-harm, 25.3% wanted to die during the most recent episode. Concurrent depression was associated with a greatly increased risk of self-harm (OR 5.43). Only 12.4% of participants sought medical help following their most recent episode of self-harm, although this figure was higher (30.1%) where self-harm was carried out with desire to die. Of the whole sample, 15.8% had ever thought of killing themselves, and 4.3% had ever made plans to kill themselves. Compared to those who had never self-harmed, those who had self-harmed but not wanted to die during the most recent episode were at increased risk of ever having had suicidal thoughts (37.6% compared to 7.8% χ2 =102.3, p < 0.001) and ever making suicidal plans (8.7% compared to 0.7%, χ2 =166.9, p < 0.001). As the frequency of self-harm increased, so did the risk of suicidal thoughts and plans.ConclusionsSelf-harm and suicidal thoughts are common among 16/17 year olds. Although the majority of self-harm behaviour is not accompanied by a desire to die, all self-harm regardless of motivation is associated with increased risk of suicidal thoughts and plans, particularly when it is carried out repeatedly.

Associations were found between teacher wellbeing and student wellbeing and psychological distress. There were also an association between teacher depression and student wellbeing. Both may be partially explained by teacher presenteeism and quality of teacher-student relationships.