School-Based Interventions for Child and Adolescent Victims of Interpersonal Violence

Abstract

Background: Interpersonal violence against children and adolescents can affect their mental health and functioning in the long term. To reduce mental health problems in children and adolescents, school-based mental health interventions have been shown to be beneficial. A review of school-based interventions designed to mitigate posttraumatic symptoms after interpersonal violence is lacking to date. Methods: We searched for original studies published in English or German until November 2019 in 6 electronic databases. Supplementary search strategies to reduce publication bias were implemented. Peer-reviewed original studies assessing school-based interventions for children and adolescents under the age of 21 after interpersonal violence were included. Relevant data was extracted, synthesised and assessed qualitatively. The methodological quality of included studies was assessed. Results: Of 5,021 unduplicated publications, 15 studies met eligibility criteria. The included studies were almost exclusively conducted in the USA; over half utilised a randomised-controlled design. Studies mainly focussed on Posttraumatic Stress Disorder (PTSD) or depression. In all studies, implemented interventions partially or fully mitigated posttraumatic symptoms. Nine school-based interventions, five of which were based on cognitive behavioural therapy (CBT), were identified. School staff were often involved in intervention implementation besides mental health professionals. Conclusions: School-based interventions can be beneficial to reduce mental health problems in children and adolescents after interpersonal violence. Trained school staff aided by mental health professionals can implement trauma-informed practices at school. While school-based interventions may be a feasible way to provide children and adolescents with accessible mental health care, further research on school-based trauma interventions outside the USA is necessary.

Keywords

child abuse violence exposure war mental health and violence treatment/intervention

Introduction

During their lives, children and adolescents can be exposed to a myriad of adverse childhood experiences, including but not limited to interpersonal violence (i.e. physical and emotional abuse or neglect, sexual, domestic or community violence, or violent experiences during war and flight). These experiences can be summarised as interpersonal (Maercker & Hecker, 2016) or complex trauma (van der Kolk, 2005). Research has shown that refugee minors, in particular those unaccompanied by adults, are especially affected by interpersonal violence not only in their countries of origin, but also during flight and after arriving in host countries (e.g. Metzner et al., 2016). For example, children of asylum seekers in Germany reported having witnessed physical violence (41%) and having experienced violence at home against other family members (26%), physical attacks against the child (15%), physical child abuse at home (14%) or sexual violence (5%) (Ruf et al., 2010). A Dutch study revealed that compared to accompanied refugee and immigrant minors, unaccompanied refugee adolescents were more often exposed to physical abuse (63% vs. 23%) or sexual violence (20% vs. 8%) and had more often witnessed physical violence (72% vs. 47%) (Bean et al., 2007). Interpersonal violence against children and adolescents is however a problem independent of ethnic background, war or conflict. A global review of meta-analyses reported lifetime prevalence rates for sexual abuse (13%), physical abuse (23%), emotional abuse (36%), physical neglect (16%) and emotional neglect (18%) according to self-report (Stoltenborgh et al., 2015). For Europe, a systematic review reported median prevalence rates for sexual abuse (13%), physical abuse (12%), emotional or psychological abuse (22%), and neglect (27%) in childhood (Moody et al., 2018). As an example of a western industrialised country with no recent war exposure, an assessment of a representative German sample of 2510 participants aged 14 to 94 resulted in prevalence rates for moderate to extreme emotional abuse (7%), physical abuse (7%), sexual abuse (8%), emotional neglect (13%) and physical neglect (22%) during childhood (Witt et al., 2017).

Psychosocial Consequences of Interpersonal Trauma in Children and Adolescents

Experiencing complex interpersonal trauma can impact children and adolescents’ physical and mental health long-term into adulthood, putting them at higher risk, for example, for Posttraumatic Stress Disorder (PTSD), depressive disorders, anxiety disorders, behavioural or conduct disorders, substance abuse, risky sexual behaviour and sexually transmitted infections, chronic disease (e.g. obesity) as well as suicidal or self-harming behaviour, with a dose–response relationship (Hughes et al., 2017; Norman et al., 2012; Perez et al., 2018; Witt et al., 2019). Research has also shown that compared to other types of trauma, interpersonal long-term trauma can result in more (potentially chronic) impairment (Maercker, 2013). For example, higher one-year and lifetime prevalence of PTSD was reported for sexual violence in adulthood (37–50%), child sexual abuse (31–35%), war-related experiences (25–39%) or child neglect (22%) compared to other types of trauma (e.g. accidents: 8–13%, witnessing accidents or violence: 2–7%, fire or natural disasters: 0–5%) (Maercker, 2013; Maercker & Hecker, 2016). A meta-analytic review of 47 studies reported a high prevalence for PTSD (35%), emotional and behavioural problems (25%), depression (21%), anxiety disorders (15%) as well as suicidal ideation and behaviour (5%) in 24,786 refugee and asylum-seeking youths residing in European countries (Kien et al., 2018). In accordance to the ‘domains of impairment in children exposed to complex trauma’ described by Cook et al. (2005, p. 392), interpersonal trauma in childhood was also found to be a risk factor for aggressive, impulsive and problem behaviour, as well as delinquent or criminal behaviour (Hughes et al., 2017; Jimenez et al., 2016; Perez et al., 2018). Especially relevant from an educational point of view, childhood interpersonal trauma can impact children and adolescents’ academic functioning and outcomes, for example resulting in attention and concentration problems, educational underachievement or learning disabilities (e.g. language and literacy skills), discipline problems and conflicts (e.g. with peers or teachers), school changes, repeating forms¹, absenteeism, or special education needs (Elklit et al., 2018; Holmes et al., 2018; Jimenez et al., 2016; Larson et al., 2017).

The Role of Schools in Providing Mental Health Care following Trauma

Children and adolescents spend a majority of their time at school and can be reached there independent of their ethnic, socioeconomic or familial backgrounds. Especially for children and adolescents who may suffer from a loss of trust in caregivers, a loss of a sense of self or low self-esteem following complex interpersonal trauma (Cook et al., 2005; van der Kolk, 2005), school staff (e.g. teachers), can serve as important attachment figures, provide support and help their pupils to re-learn trust in others. Therefore, schools can serve not only as practical locations to implement and provide interventions and mental health care services, but also as places of resilience (Gerke et al., 2019). For example, in a German survey of people who had suffered sexual violence and contacted a helpline for sexual abuse, participants reported that their well-being was positively affected by their teachers’ reactions and support following disclosure, and that an ongoing interest in their experience was perceived as helpful (Gerke et al., 2019).

In recent years, the benefit of school-based interventions or trauma-focussed practices for children and adolescents has been assessed in systematic reviews (Rolfsnes & Idsoe, 2011; Yohannan & Carlson, 2019; Zakszeski et al., 2017). Rolfsnes and Idsoe (2011) for example assessed the effectiveness of school-based interventions for children and adolescents suffering from PTSD after traumatic events in a meta-analysis of 19 international studies. Their results showed not only that school-based interventions were effective in reducing PTSD symptoms, but also that school staff (e.g. counsellors or teachers) were able to successfully implement the interventions, and that intervention access and completion rate was higher within the school setting compared for example to a clinical setting (Rolfsnes & Idsoe, 2011). Zakszeski et al. (2017) conducted a systematic review of 39 international studies and found that trauma-focussed practices within schools largely led to mitigation of posttraumatic symptoms and internalising problems following trauma exposure. Yohannan and Carlson (2019) assessed 41 international evaluation studies of school-based interventions, concluding that these interventions can help to mitigate posttraumatic outcomes in children after traumatic events. These systematic reviews however did not restrict the trauma exposure to specific events, instead including all types of trauma (e.g. natural disasters) and thus had very heterogenous samples.

Aims of This Systematic Review

Past research has shown the benefit of school-based services for children and adolescents following trauma exposure. However, a comprehensive systematic review on school-based interventions for children and adolescents targeting posttraumatic outcomes specifically after interpersonal violence is lacking to our knowledge. With view to the potentially severe and long-term mental health outcomes following complex interpersonal trauma, there appears to be a substantial gap in research. The current systematic review aims to close this gap by identifying and describing school-based interventions designed to mitigate psychosocial posttraumatic symptoms in children and adolescents after interpersonal violence.

Methods

The methods of this systematic review are based on guidelines for implementation and analysis of systematic literature reviews (e.g. Higgins et al., 2019; Moher et al., 2009).

Search Strategy

Using the psychological, medical and pedagogical literature databases PSYNDEX, PsycINFO, Medline, CINAHL, ISI Web of Science (subcategory Social Science) and ERIC, original studies published until 20 November 2019 were systematically searched. The search results were limited to journal articles in English or German language. An overview of English and German search terms used in the database search is found in Table 1. The search included experiences of war as well as refugee samples, as these children and adolescents were regarded as relevant samples due to the range and prevalence of interpersonal violence experiences in the context of war (Bean et al., 2007; Metzner et al., 2016; Ruf et al., 2010). In an effort to reduce publication bias, a supplementary literature search was conducted: reference lists of relevant studies and literature reviews were searched manually, Google Scholar was utilised for a manual search, and authors of included publications were contacted for further relevant studies that may have been missed via systematic database and supplementary search.

Table 1.

Terms Used in Systematic Database Literature Search.

Category	English Language	German Language
A: interpersonal violence	Interpersonal violence OR Sexual abuse OR Child abuse OR Maltreatment OR Neglect OR Domestic violence OR Refuge* OR Flight OR Asylum* OR War*	Interpersonell* gewalt* OR Sexuell* missbrauch* OR Kindesmisshandlung* OR Misshandlung* OR Vernachlaessigung* OR Haeuslich* gewalt* OR Fluechtling* OR Flucht* OR Asyl* OR Krieg*
B: posttraumatic disorder	Trauma related disorder* OR Ptsd OR Complex posttraumatic stress* OR Complex Ptsd OR Posttraumatic stress*	Traumafolgestoerung* OR Posttraumatisch* belastungsstoerung* OR Ptbs OR Komplex* posttraumatisch* belastungsstoerung* OR Komplex* ptbs OR Posttraumatisch* stress*
C: functional impairment	School absentee* OR School dropout* OR School expulsion OR School exclusion OR Change of school* OR Grade retention* OR Behavior* problem* OR Discipline problem* OR School performance* OR Learning disorder* OR Concentration*	Schulabsentismus OR Schulverweis* OR Schulausschluss OR Schulabbr* OR Schulwechsel OR Klassenwiederholung* OR Verhaltensauffaellig* OR Disziplinproblem* OR Schulleistung* OR Lernstoerung* OR Konzentration*
D: population	Child* OR Adolescent* OR Teen* OR Minor* OR Young adult* OR Student*	Kind* OR Jugendlich* OR Minderjaehrig* OR Junge* erwachsene* OR Schueler*
E: school	School*	Schul*
F: interventions	Intervention* OR Treatment* OR Therap* OR Counsel* OR Program*	Intervention* OR Berat* OR Behandlung* OR Therap* OR Programm*

Notes. Categories were combined into a search string as follows: A and (B or C) and D and E and F, resulting in both an English language and a German language search string.

Selection Process

The systematic database search yielded 6,237 results, with an additional 50 publications identified via supplementary search. After removal of duplicates, 5,021 publications remained (see Figure 1). Two independent reviewers (graduated psychologists) screened the remaining publications for conformity with inclusion criteria using title, abstract and keywords (see Table 2).

Figure 1.

PRISMA-flow-diagram for the presentation of study selection process (Moher et al., 2009).

Table 2.

Inclusion and Exclusion Criteria Based on PICOS-Scheme.

Inclusion Criteria (IC)
P opulation
IC 1	Children and adolescents (0–21 years)
IC 2	At least 1 traumatic experience of interpersonal violence present in at least 50% of the sample a. Abuse (physical, psychological, emotional) b. Neglect (physical, psychological, emotional) c. Witnessing violence (domestic, community) d. Sexual violence/abuse e. Interpersonal violence in the context of war (e.g. torture, killings, attacks, persecution)
IC 3	At least 1 psychosocial consequence of the traumatic experience a. Posttraumatic disorder(s) b. Functional impairment (at school)
I ntervention
IC 4	Intervention aims at IC 3 (consequence of trauma)
IC 5	Intervention is school-based a. Before, during or after lessons b. On school premises c. Implemented by school staff or external professionals
O utcome
IC 6	Mitigation/improvement of IC 3 (consequences of trauma)
S tudy Design
IC 7	Intervention study (RCT) or observational study (e.g. cohort, follow-up, case-control, cross-sectional, pre-post)
Publication
IC 8	Peer-reviewed original study (journal article)
IC 9	Published in English or German language
Exclusion Criteria (EC)
EC 1	Trauma due to accidents, natural disaster, terror attacks, experience of war without interpersonal violence (e.g. shooting, bombardment), death of an attachment figure due to age/illness/accident/natural disaster/terror attacks
EC 2	Exclusively bullying or hazing behaviour among peers, classmates, etc.
EC 3	Exclusively medical consequences of trauma (e.g. physical injuries)
EC 4	Functional impairment at school not caused by traumatic experience (e.g. by other psychological impairment, developmental delay)
EC 5	Medical services for children and adolescents regarding consequences of trauma (e.g. physiotherapy)

Notes. No inclusion criteria were specified for Comparators, as both controlled and non-controlled study designs were of interest for this systematic review.

After screening, the full-texts of 164 publications were considered eligible for inclusion into the systematic review and assessed by the independent reviewers regarding their conformity with inclusion criteria (see Figure 1). The reviewer assessments matched in 80% of publications, resulting in a moderate inter-rater reliability (κ = .56; Altman, 1999). The independent reviewers were not blind to authors and journal of the assessed publications in either step. In cases of differing assessments, the publication in question was discussed until consensus was reached. In cases of publications examining the same sample, only the publication with most relevant data for the current systematic review was included into data synthesis.

Data Extraction and Synthesis

After reviewing the full-texts against the inclusion criteria, 15 studies were included into the systematic review. Using a structured table for data synthesis, two independent reviewers first extracted and coded relevant information for describing the studies included: country where the study was conducted, methodology (e.g. study design, data collection, control group, posttraumatic outcomes assessed), sample characteristics (e.g. size, age and gender distribution, trauma exposure), and intervention outcome. Next, the independent reviewers extracted and coded information about the school-based interventions described in the studies included: name and acronym, studies utilising the intervention (or a modification thereof), and intervention characteristics (e.g. primary goal, target population, type of intervention, implementation at school, duration, contents or components). In case of mixed-methods studies, only quantitative methods and data were extracted. If the information extracted from the studies differed between the first and second reviewer, a third reviewer was consulted. No authors of studies included were contacted for further information or data.

Methodological Quality Assessment

The methodological quality of the studies included was assessed by two independent reviewers using the Mixed Methods Appraisal Tool (MMAT; Hong et al., 2018).

The Mixed Methods Appraisal Tool

The MMAT (Hong et al., 2018) was developed for methodological quality assessment of empirical studies included in systematic reviews comprising different study designs. Overall, five types of study designs can be assessed using the MMAT: qualitative, quantitative randomised controlled trials (RCTs), quantitative non-randomised, quantitative descriptive and mixed methods. Methodological quality is assessed first using two screening questions (applicable to all study designs). If one or both screening questions are not met, further assessment ‘may not be feasible or appropriate’ (Hong et al., 2018, p. 2). Second, methodological quality is assessed with five quality criteria particular to each study design. Due to the current systematic review’s focus on intervention studies, quality criteria for only two relevant study designs (quantitative RCTs and quantitative non-randomised) were applied. For quantitative RCTs, following quality criteria were assessed: (1) ‘Is randomi[s]ation appropriately performed?’, (2) ‘Are the groups comparable at baseline?’, (3) ‘Are there complete outcome data?’, (4) ‘Are outcome assessors blinded to the intervention provided?’, and (5) ‘Did the participants adhere to the assigned intervention?’ (Hong et al., 2018, p. 2). For quantitative non-randomised studies, following quality criteria were assessed: (1) ‘Are the participants representative of the target population?’, (2) ‘Are measurements appropriate regarding both the outcome and intervention (or exposure)?’, (3) ‘Are there complete outcome data?’, (4) ‘Are the confounders accounted for in the design and analysis?’, and (5) ‘During the study period, is the intervention administered (or exposure occurred) as intended?’ (Hong et al., 2018, p. 2).

Methodological quality assessment procedure

The independent reviewers assessed the quality of included studies using first the screening questions for all study categories, and second the five quality criteria particular to each study design. In case of mixed-methods studies, only the quality of quantitative methodology was assessed. Disagreements in assessment were resolved through discussion. The screening questions and quality criteria were assessed as ‘met’, ‘not met’ or ‘not enough information available’, resulting in a global assessment of methodological quality (high, medium, low). Both screening questions had to be met; if one or more screening questions were assessed as ‘not met’ or ‘not enough information available’, the study quality was immediately judged as ‘low’, regardless of quality criteria assessment. After screening, the included studies’ methodological quality was further assessed using the five quality criteria, resulting in overall ratings of high (all quality criteria met), medium (3–4 quality criteria met) or low (0–2 quality criteria met) methodological quality.

Results

Overall, k = 15 publications were included into the systematic review. All publications passed methodological quality screening. Subsequently, study quality was rated high for k = 2 studies, medium for k = 9 studies and low for k = 4 studies (see Table 3). The characteristics and reported results of the studies included are presented below.

Table 3.

Methodological Quality Assessment of Studies Included in the Systematic Review Based on MMAT Criteria (k = 15).

	Barron et al. (2013)	Beehler et al. (2012)	Brown & Block (2001)	Carbonell & Parteleno-Barehmi (1999)	Carrion et al. (2013)	Crosby et al. (2019)	Ehntholt et al. (2005)	Goodkind et al. (2010)	Hoover et al. (2018)	Jaycox et al. (2009)	Kataoka et al. (2003)	Perry & Daniels (2016)	Santiago et al. (2018)	Stein et al. (2003)	Tol et al. (2012)
Screening
1. Clear research questions	+	+	+	+	+	+	+	+	+	+	+	+	+	+	+
2. Data address research questions	+	+	+	+	+	+	+	+	+	+	+	+	+	+	+
Quantitative RCT
1. Randomisation appropriately performed	+		0	0	+					0	–		+	+	0
2. Group characteristics comparable at baseline	+		+	+	+					+	0		+	+	+
3. Complete outcome data available	+		–	+	–					+	+		+	+	+
4. Outcome assessors blinded to intervention	0		0	0	0					0	0		0	–	+
5. Participants adhered to assigned intervention	+		0	+	–					–	+		+	+	+
Quantitative non-randomised studies
1. Participants representative of target population		+				+	–	+	+			0
2. Measurements appropriate for outcome and intervention		+				+	+	+	+			+
3. Complete outcome data available		+				+	+	+	+			+
4. Confounders accounted for in design and analysis		+				–	–	+	–			–
5. Intervention administered as intended during study period		+				+	+	+	+			+
Overall assessment	M	H	L	M	L	M	M	H	M	L	L	M	M	M	M

Notes. + quality criterion met, – quality criterion not met, 0 = not enough information available; H = high study quality (all quality criteria and both screening questions met), M = medium study quality (1–2 quality criteria not met or not enough information available, and both screening questions met), L = low study quality (more than 2 quality criteria not met or not enough information available, or at least 1 screening question not met).

Study Characteristics

The included intervention studies were published between 1999 and 2019 and comprise k = 13 quantitative and k = 2 mixed-methods studies. Over half of the studies included (k = 9) conducted an RCT; a pre-post study design was chosen in k = 5 studies. Of the k = 10 studies including a control group, almost all (k = 9) utilised a waitlist control condition (see Table 4). The majority of studies was conducted in the USA (k = 12; 80%), with k = 1 study each conducted in the Palestinian territories, the UK and Sri Lanka (see Table 4).

Table 4.

Description of Studies Included in the Systematic Review (k = 15).

First Author (Year) [Country]	Study Design (Methods) [Control]	Sample Size: n (% Female)	Age in Years M (SD) [Range]	Type(s) of Trauma	Assessed Posttraumatic Outcomes						Intervention Outcome
First Author (Year) [Country]	Study Design (Methods) [Control]	Sample Size: n (% Female)	Age in Years M (SD) [Range]	Type(s) of Trauma	Anxiety	Depression	EBP	Functioning	PTSD	Other	Intervention Outcome
Barron (2013) [Palestinian territories]	RCT (quantitative) [waitlist]	Total: 140 (na)IG: 90 (39) CG: 50 (50)	Total: naIG: 11.1 (1.2) [11–14]CG: 11.1 (0.7) [11–13]	War		×			×	×	Depression: +PTSD: +Other: +
Beehler (2012) [USA]	Pre-post (quantitative) [–]	149 (63)	14.4 (2.9) [6.4–21]	War, flight/emigration, child endangerment^b				×	×		Functioning: +PTSD: 0
Brown (2001) [USA]	RCT with follow-up (mixed-methods) [limited voluntary services]	Total: 1108 (100)IG: na (100)CG: na (100)	Total: 15.2 (na) [14–17]IG: naCG: na	Abuse (physical, emotional, sexual)		×				×	Depression: –Other: 0
Carbonell (1999) [USA]	RCT (mixed-methods) [waitlist]	Total: 28 (100)IG: 12 (100)CG: 14 (100)	Total: na (na) [11–13]IG: naCG: na	Child endangerment^b			×				EBP: 0
Carrion (2013) [USA]	RCT (quantitative) [waitlist]	Total: 65 (40)IG: 38 (42)CG: 27 (37)	Total: 11.6 (1.9) [8–17]IG: 11.7 (2.1) [na]CG: 11.5 (1.7) [na]	Child endangerment^b	×	×		×	×		Anxiety: 0Depression: 0Functioning: +PTSD: +
Crosby (2019) [USA]	Pre-post (quantitative) [–]	109 (100)	15.9 (1.3) [na]	Abuse, neglect					×		PTSD: +
Ehntholt (2005) [UK]	Non-RCT^a with follow-up (quantitative) [waitlist]	Total: 26 (35)IG: 15 (33)CG: 11 (36)	Total: na (na) [11–15]IG: 12.5 (0.7) [na]CG: 13.5 (1.1) [na]	War, flight	×	×	×		×		Anxiety: 0Depression: –EBP: +PTSD: +
Goodkind (2010) [USA]	Pre-post with follow-up (quantitative) [–]	23 (70)	13.4 (na) [12–15]	Exposure to violence	×	×			×	×	Anxiety: +Depression: 0PTSD: 0Other: +
Hoover (2018) [USA]	Pre-post (quantitative) [–]	350 (60)	12.2 (2.4) [8–19]	Child endangerment^b			×	×	×		EBP: +Functioning: +PTSD: +
Jaycox (2009) [USA]	RCT with follow-up (quantitative) [waitlist]	Total: 76 (51)IG: 39 (54)CG: 37 (49)	Total: 11.5 (0.7) [na]IG: 11.4 (0.6) [na]CG: 11.5 (0.7) [na]	Child endangerment^b, exposure to violence		×	×		×		Depression: +EBP: –PTSD: 0
Kataoka (2003) [USA]	(Partly cluster) RCT with follow-up (quantitative) [waitlist]	Total: 229 (50)IG: 182 (51)CG: 47 (47)	Total: 11.4 (1.7) [na]IG: 11.5 (1.8) [na]CG: 11.2 (1.5) [na]	Exposure to violence		×			×		Depression: +PTSD: 0
Perry (2016) [USA]	Pre-post (quantitative) [–]	77 (na)	na	Exposure to violence					×	×	PTSD: 0Other: +
Santiago (2018) [USA]	Cluster RCT with follow-up (quantitative) [waitlist]	Total: 52 (35)IG: 25 (36)CG: 27 (37)	Total: 7.8 (0.9) [na]IG: 7.7 (0.8) [na]<CG: 7.8 (1.0) [na]	Exposure to violence, child endangerment^b	×	×	×		×	×	Anxiety: –Depression: 0EBP: –PTSD: +Other: +
Stein (2003) [USA]	RCT with follow-up (quantitative) [waitlist]	Total: 126 (na)IG: 61 (54)CG: 65 (58)	Total: naIG: 11.0 (0.3) [na]CG: 10.9 (0.4) [na]	Exposure to violence		×	×		×		Depression: +EBP: +PTSD: +
Tol (2012) [Sri Lanka]	Cluster RCT with follow-up (quantitative) [waitlist]	Total: 399 (39)IG: 199 (38)CG: 200 (39)	Total: 11.0 (1.1) [9–12]IG: naCG: na	War/political conflict	×	×	×	×	×	×	Anxiety: –Depression: –EBP: –Functioning: –PTSD: –Other: +

Notes. Reported sample sizes refer to sizes at baseline; * mental and emotional health/well-being; ^a non-randomised controlled trial, ^b child endangerment is used as a broad category for potential exposure to all types of danger to a minor’s wellbeing (e.g. abuse, neglect and sexual violence); CG = control group, GPA = grade point average, IG = intervention group, na = not available, EBP = emotional/behavioural problems, PTSD = Posttraumatic Stress Disorder; percentages were rounded to whole numbers, mean and standard deviation of age were rounded to one decimal place.

Sample Characteristics

Only counting intervention groups, sample sizes ranged from n = 12 to n = 350, with a total of n = 1369 children and adolescents receiving treatment interventions included across all studies (information available for k = 14 studies). The percentage of female intervention group participants ranged from 33% to 100% and was unknown for k = 1 study. Intervention group participants were on average 12.1 years old (information available for k = 11 studies). Only k = 4 studies reported age ranges for their intervention groups, resulting in an overall range of 6–21 years (see Table 4). The study samples included were generally exposed to violence (k = 6 studies) or child endangerment (k = 6 studies). Samples in k = 4 studies had experienced war and conflict in their countries of origin (Palestinian Territories, Barron et al., 2013; Sri Lanka, Tol et al., 2012) or were forced to flee or emigrate from their countries of origin (Beehler et al., 2012; Ehntholt et al., 2005) (see Table 4). The refugee samples were ethnically diverse, originating from five (Ehntholt et al., 2005) to nine (Beehler et al., 2012) different regions.

Assessed Posttraumatic Outcomes

Almost all studies assessed PTSD (k = 13) or depression (k = 10) as posttraumatic outcomes. Emotional or behavioural problems were assessed in k =7, anxiety in k = 5 and global functioning in k = 4 studies. In k = 6 studies, other posttraumatic outcomes (e.g. coping behaviour, substance use, grief, global mental health) were assessed. Furthermore, one study (Barron et al., 2013) assessed school performance as outcome (see Table 4). Instruments most frequently used to measure PTSD symptoms were the Childhood PTSD Symptom Scale (Foa, Treadwell, Johnson & Feeny, 2001) (k = 6) and the UCLA PTSD Reaction Index (Pynoos et al., 1998) (k = 4). Depression was mainly measured using the Children’s Depression Inventory (Kovacs, 1992) (k = 6) and the Depression Self-Rating Scale (Birleson, 1981) (k = 3). Self- and third-party-report versions of the Strengths and Difficulties Questionnaire (Goodman, 1997) were most frequently used to measure emotional and behavioural problems (k = 4).

Reported Intervention Outcomes

While not all implemented interventions significantly improved all posttraumatic outcomes, positive intervention effects (fully or partially significant, or approaching significance) were reported in the majority of included studies. For PTSD symptoms, 92% of relevant studies reported full (k = 7) or partial (k = 5) mitigation, while depressive symptoms were mitigated fully (k = 4) or partially (k = 3) in 70% of relevant studies. Emotional and behavioural problems and anxiety fully or partially improved in about 60% of relevant studies (k = 4 and k = 3, respectively). Functioning fully improved as a result of the implemented intervention in three of k = 4 relevant studies (see Table 4).

Description of Implemented Interventions

An overview of implemented interventions across all studies included is presented in Table 5.

Table 5.

Description of Interventions Implemented in the Studies Included in the Systematic Review (k = 15).

Intervention (Acronym) [Publication]	Primary Goal (Target Population) [Type/Basis]	Implementation at School (Setting)	Duration	Implementing person(s)	Contents/Components/Modules
Manualised or standardised interventions
Cognitive Behavioral Intervention for Trauma in Schools^a (CBITS) [8, 9, 10, 11, 13, 14]	Reduction of PTSD, anxiety & depressive symptoms; improvement of coping & functioning (pupils in forms 5 to 12 with trauma history) [CBT]	Extracurricular during school day (group & individual)	10 weekly group & 2 individual sessions during one class period (with modifications)	School-based clinicians/social workers/psychologists/mental health workers	a. Introduction/psychoeducation (session 1–2)b. Relaxation training (session 2)c. Thoughts/feelings/fear thermometer (session 3)d. Combating negative thoughts (session 3–4)e. Avoidance/coping/fear hierarchy (session 5)f. Exposure by imagination/writing/drawing (session 6–7)g. Social problem solving (session 8–9)h. Relapse prevention/graduation (session 10)Individual sessions (imaginal exposure) between sessions 2 & 6.(with modifications)
Psychodrama Group^b (−) [4]	Addressing trauma experiences & resulting difficulties (traumatised children) [–]	Extracurricular during school day (group & individual)	20 weeks	Clinical social worker	a. Warm-up: introductions, building cohesion & trust, setting rules, finding commonalities, introduction of core ideas & techniques of psychodrama, building a baseb. Action: re-enactment of traumatising eventc. Sharing: talking about feelings evoked through psychodrama & individual experience, reflection of goals of containment, connection to others, choice & self-efficacy in last exercise
Stanford cue-centred treatment^c (−) [5]	Building strength & resilience (youth with repeated exposure to trauma or adverse conditions) [integrative approach]	Extracurricular during school day (individual)	15 weekly 50-minute sessions	Licensed therapists	Psychoeducation of young people & caregivers in 4 core domains: cognition, behaviour, emotions, physiologya. Significance of traumatic stress, maladaptive responses, coping with versus avoiding ongoing stress, importance of verbalising life experiencesb. Recognising & effectively managing maladaptive responses to traumatic reminders (cues)c. Overall competence building, physical symptom reduction of anxiety, modifying cognitive distortions, facilitating emotional expression
Teaching Recovery Techniques^d (TRT) [1*, 7]	Education on PTSD symptoms, teaching adaptive coping strategies (children exposed to war/conflict aged 8+ years) [CBT]	Extracurricular during school day (group)	Originally designed as 5 sessions, 2 hours each (with modifications)	(School) counsellors/psychologists (in training)	a. Incorporation of psychoeducation, imagery & relaxation techniques, coping strategies within sessionsb. Addressing symptoms of intrusion, arousal, avoidance (with modifications)
The Heart of Teaching and Learning: Compassion, Resiliency, and Academic Success^e (HTL) [6*]	Increase self-worth & self-love, perception of relationships as positive/rewarding (pupils) [teacher training]	Trauma-sensitive teaching (−)	Teacher training: annual curriculum with 8 half-day trainings; monthly 2-hour booster sessions	Clinical social worker (teacher training), teachers (at school)	a. Background & definitions of traumab. Compassionate schools & survivalc. Self-cared. Curriculum domains & specific strategiese. Collaborative problem solvingf. Role plays, games, case vignettes.Additional classroom implementation: Monarch Room (brief intervention strategies for emotion regulation)
na^f [15]	Improve coping behaviour to reduce psychological symptoms (children affected by war) [CBT & creative expressive elements]	na (group)	15 sessions over 5 weeks	“Non-speciali[s]ed personnel” (p. 116)	a. Information, safety, control (sessions 1–3)b. Stabilisation, awareness, self-esteem (sessions 4–6)c. Trauma narrative (sessions 7–9)d. Resource identification, coping skills (sessions 10–12)e. Re-connection with social context, future planning (sessions 13–15)
Interventions with manualised or standardised components
Cultural Adjustment and Trauma Services (CATS) [2]	Improve functioning, PTSD symptoms (immigrant children with trauma exposure/cultural adjustment needs) [mental health service program incl. (TF-)CBT^g]	Counselling & support at school (group & individual)	na	Licensed clinicians, cultural mediators	a. Relationship-buildingb. Outreach services (cultural mediators acting as link to mental health services with goal of early identification & treatment of mental health problems; provision of informal tangible/supportive services, brief clinical interventions e.g. relaxation training)c. Clinical & case management services (trauma-informed, client-centred, addressing a range of issues e.g. symptoms, resettlement concerns, other stressors; impact on various levels: school & community, family, individual; use of CBT and TF-CBT in case of specific traumatic events)
New Haven Trauma Coalition (NHTC) [12]	Implementing trauma-informed systems at school, identifying pupils in need, psychoeducation (pupils in need of trauma-informed support) [trauma-informed education, CBITS^a]	Trauma-sensitive practices, clinical services: workshop, CBITS during school day** (classroom/group)	Teacher/administrator training: 2 daysClinical services:workshops: 3 daysCBITS: 10 weeks	Coordinators, clinicians, teachers	a. Professional development: school staff training (lectures, workshops) teaching strength-based interactions, trauma-informed classroom activities, de-escalation, staff self-care, adverse life experiences, developing trust, motivational interviewingb. Clinical services: workshop for pupils based on survey on topics of interest (making friends, trusting others, learning how to relax when feeling angry/sad/scared), CBITS
Non-manualised or non-standardised interventions
Project Chrysalis^h (−) [3]	Reduction of substance use & negative consequences following physical/sexual/emotional abuse; improvement of health (behaviour), school performance, self-determination, independence, self-image (female adolescents in forms 9–12) [support group]	Extracurricular during school day (group & individual)	Participation as (in-)frequently as needed/desired throughout one school year; educational sessions open up to 1 year after participation	School counsellors, therapists	Multifaceted approach with various strategies; impact on domains of individual, school, peers, communitya. Individual: school-based support groups, informational handouts, journal keeping (causes & effects of abuse, risky behaviours & coping strategies, impact of abuse on intimacy/sexuality, recovery techniques)b. School: individual case management (reinforcement of support groups, available on demand)c. Peers/community: periodical educational open sessions incl. guest speakers (substance use prevention, tobacco awareness, eating disorders, HIV/AIDS education, self-defence, physical endurance)

Notes. 1 = Barron et al. (2013), 2 = Beehler et al. (2012), 3 = Brown & Block (2001), 4 = Carbonell & Parteleno-Barehmi (1999), 5 = Carrion et al. (2013), 6 = Crosby et al. (2019), 7 = Ehntholt et al. (2005), 8 = Goodkind et al. (2010), 9 = Hoover et al. (2018), 10 = Jaycox et al. (2009), 11 = Kataoka et al. (2003), 12 = Perry & Daniels (2016), 13 = Santiago et al. (2018), 14 = Stein et al. (2003), 15 = Tol et al. (2012).

^aJaycox (2004).

^bJohnson et al. (1995).

^cCarrion (2015).

^dSmith et al. (2000).

^eWolpow et al. (2009).

^fMacy et al. (2003).

^gCohen et al. (2004).

^hMcClarty & Selmer (2000).

* adapted or translated manual, ** the NHTC intervention also included a care coordination component (facilitation of relationship-building and dialogue between schools and families) not further described in this review as it was not strictly school-based; (TF-)CBT = (trauma-focussed cognitive-behavioural therapy, na = information not available.

Overall, nine different interventions were implemented across all k = 15 studies. Almost all interventions had no gender restrictions, the only exception being Project Chrysalis (Brown & Block, 2001) which solely addressed females who had experienced physical, emotional or sexual abuse. Two further interventions however were implemented in all-female samples (Psychodrama Groups, Carbonell & Parteleno-Barehmi, 1999; HTL, Crosby et al., 2019). Of the k = 4 studies assessing war- and flight-related trauma, all implemented interventions specifically addressed war-related trauma or culture-sensitive needs, and k = 2 studies (Beehler et al., 2012; Ehntholt et al., 2005) implemented their interventions in ethnically diverse refugee or immigrant samples.

The majority of interventions was manualised or standardised (6/9) or integrated a manualised or standardised component (2/9); for a short description of the interventions see Table 5. In k = 6 studies, the authors implemented an adapted (e.g. according to local needs and resources) or translated version of a manualised intervention. Five interventions in k = 11 studies were based on (trauma-focussed) cognitive behavioural therapy (CBT) or used CBT-based components (see Table 5), of which k = 5 studies achieved complete mitigation of posttraumatic outcomes (see Table 4). The primary goals of the interventions implemented were largely building resilience and coping strategies (6/9), mitigation of posttraumatic symptoms and problems (e.g. PTSD, depression, anxiety, psychological distress) (5/9) and improving functioning (2/9). About half (i.e. five) of the interventions were implemented as extracurricular sessions during the school day (k = 11 studies), while one intervention consisted of counselling and support at school (Beehler et al., 2012) and another implemented trauma-sensitive teaching at school using teacher trainings (Crosby et al., 2019). One intervention described by Perry and Daniels (2016) implemented both trauma-sensitive practices within the school and extracurricular clinical services. Overall, four interventions (k = 9 studies) utilised group settings with individual components, three interventions (k = 4 studies) utilised pure group settings, and one intervention (k = 1 study; Carrion et al., 2013) offered purely individual treatment (see Table 5). The implemented interventions’ duration varied, with the number of sessions necessary ranging between 5 and 20. One intervention (Project Chrysalis; Brown & Block, 2001) allowed for pupils to participate as (in-)frequently as per their needs throughout one school year. The persons implementing the interventions across the included studies mainly comprised mental health professionals (e.g. clinicians, psychologists, counsellors, therapists). Five interventions described in k = 11 studies included school personnel in implementation, two of which utilising trauma-sensitive teaching and practices (Crosby et al., 2019; Perry & Daniels, 2016) were implemented by teachers within the school or had teachers participating in the implementation process (see Table 5).

Two interventions were implemented in more than one study: Teaching Recovery Techniques (TRT; Smith et al., 2000) (k = 2 studies) and Cognitive Behavioral Intervention for Trauma in Schools (CBITS; Jaycox, 2004) (k = 6 studies, with k = 1 further study utilising CBITS as an intervention component). One study implementing TRT each achieved full (Barron et al., 2013) or partial (Ehntholt et al., 2005) mitigation of posttraumatic outcomes (see Table 4). Three studies (Hoover et al., 2018; Kataoka et al., 2003; Perry & Daniels, 2016) implementing CBITS or using CBITS as an intervention component achieved complete mitigation of posttraumatic outcomes, while four studies achieved partial mitigation (Goodkind et al., 2010; L. H. Jaycox et al., 2009; Santiago et al., 2018; Stein et al., 2003) (see Table 4).

Discussion

The current systematic review aimed at identifying and describing school-based interventions designed to mitigate posttraumatic outcomes in children and adolescents after interpersonal violence. The results show that school-based interventions can be a beneficial approach in improving posttraumatic symptoms, especially PTSD, after complex interpersonal trauma, with all intervention studies described in this review achieving partial or full symptom mitigation for at least one posttraumatic outcome.

Discussion of Current Findings

Similar to findings of previous reviews (Rolfsnes & Idsoe, 2011; Stratford et al., 2020; Yohannan & Carlson, 2019; Zakszeski et al., 2017), the majority of studies implemented a CBT-based intervention with CBITS being the most common approach. The included studies rarely assessed only specific traumatic experiences, but rather cumulative and complex experiences of general violence in the children and adolescents’ environment, child endangerment or war-related trauma, with a particular focus on PTSD and depression as posttraumatic outcomes. Although outcomes like anxiety, academic and global functioning or emotional and behavioural problems have been assessed in some of the included studies, in view of the wide range of psychological, behavioural and socio-emotional consequences complex interpersonal trauma can have on children and adolescents (e.g. Elklit et al., 2018; Holmes et al., 2018; Hughes et al., 2017; Perez et al., 2018), research on school-based interventions targeting these other posttraumatic outcomes seems to be insufficient. With the addition of Complex PTSD (C-PTSD) into the current International Classification of Diseases (ICD-11; World Health Organization, 2020), a diagnosis that takes behavioural, socio-emotional and cognitive symptoms specific to complex trauma into account has become available. As C-PTSD is still a very recent addition, increased research on this diagnosis and possible effects of (school-based) interventions is to be expected in the upcoming years, prospectively adding to empirical knowledge about a broader range of posttraumatic symptoms. As perhaps the most interesting finding pertaining to school-based intervention research, in accordance with the findings of Rolfsnes and Idsoe (2011), trained school-based personnel (e.g. school counsellors, teachers) aided by mental health professionals were involved in the implementation process in almost all studies, for example establishing trauma-informed practices at school (Crosby et al., 2019; Perry & Daniels, 2016). An overview of critical findings is provided in Table 6.

Table 6.

Summary of Critical Findings.

Critical Findings
⁃ The current findings should not be generalised for populations outside the USA.⁃ School-based interventions can be beneficial for the reduction of posttraumatic symptoms in children and adolescents after interpersonal violence.⁃ CBT-based interventions seem to be the most common approach.⁃ School-based intervention research seems to put a large focus on PTSD and depression as posttraumatic outcomes.⁃ Central aims of school-based interventions seem to be mitigating posttraumatic symptoms and building resilience or coping strategies.⁃ Trained school personnel supported by mental health professionals can successfully implement interventions aimed at mitigating posttraumatic symptoms in children and adolescents after interpersonal violence.

Critical Findings

⁃ The current findings should not be generalised for populations outside the USA.⁃ School-based interventions can be beneficial for the reduction of posttraumatic symptoms in children and adolescents after interpersonal violence.⁃ CBT-based interventions seem to be the most common approach.⁃ School-based intervention research seems to put a large focus on PTSD and depression as posttraumatic outcomes.⁃ Central aims of school-based interventions seem to be mitigating posttraumatic symptoms and building resilience or coping strategies.⁃ Trained school personnel supported by mental health professionals can successfully implement interventions aimed at mitigating posttraumatic symptoms in children and adolescents after interpersonal violence.

Diversity and generalisability

The current findings indicate that the interventions described in the included studies are gender-inclusive and able to address samples with diverse needs. As mentioned above, with the exception of Project Chrysalis (Brown & Block, 2001), no intervention had gender restrictions. Furthermore, there was a broad range of interpersonal trauma experiences in the samples assessed, with only two studies (Brown & Block, 2001; Crosby et al., 2019) focussing on specific types of interpersonal violence. Interventions addressing war- and flight-related trauma generally had culture- or war-sensitive content and were in part implemented in ethnically diverse samples (e.g. Beehler et al., 2012; Ehntholt et al., 2005). While these findings might seem to point to a broad applicability of the interventions described in the included studies, one factor limiting a generalisation of the current findings needs to be considered: consistent with previous findings (e.g. Yohannan & Carlson, 2019; Zakszeski et al., 2017) the overwhelming majority of research was based in the USA. Given the US-based Trauma and Learning Policy Initiative (TLPI), first introduced in 2005 and further developed into a framework for action in 2013 (Massachusetts Advocates for Children, MAC, 2009, 2013), this finding is not surprising. The TLPI is in its core a research-based project to reform and develop schools, introducing trauma-informed practices and teaching (MAC, 2009, 2013) and consequently impacting US-American policy, practice and research. While the USA has effectively become a pioneer in school-based trauma-informed practices and research, there is a dearth of school-based intervention research targeting consequences of complex interpersonal trauma in other parts of the world. As such, taking global differences in populations, mental health care services and school systems into account, the findings of the current review cannot be generalised for populations outside the USA.

Excluded studies

During the selection process of studies to be included in data extraction and synthesis, the two reviewers agreed in 80% of assessments, resulting in only moderate inter-rater reliability. This can be attributed to an initially high level of disagreement about trauma exposure as described by inclusion criterion 2 and exclusion criterion 1, accounting for 64% of all disagreements. Initially, inclusion criterion 2 was determined as the population being exposed to at least one interpersonal traumatic experience without specifying what percentage of the sample had to have experienced interpersonal violence. This definition emerged as not precise enough for clear decision-making, even when taking exclusion criterion 1 (traumatic experience without interpersonal component) into account: The study samples had experienced a range of traumatic events, including non-interpersonal trauma (e.g. shelling, bombings, accidental injury or death of a loved one). For many studies, it was not evident to the reviewers whether interpersonal violence was the predominant traumatic event, in turn leading to disagreements in their decisions. Thus, inclusion criterion 2 was specified during the data extraction and synthesis process in order to create a more homogenous overall sample, improve decision-making and to increase comparability of included study samples. Consequently, 13 studies had to be retroactively excluded from data extraction and synthesis because they (a) did not provide enough information to judge whether interpersonal violence was the predominant traumatic experience, or (b) fell below the 50% cut-off now defined in inclusion criterion 2 (see Table 7).

Table 7.

Overview of Retroactively Excluded Studies.

First author (year)	Title
Baum (2013)	Training teachers to build resilience in children in the aftermath of war: A cluster randomized trial
Diab (2015)	Effectiveness of psychosocial intervention enhancing resilience among war-affected children and the moderating role of family factors
Ellis (2012)	Multi-tier mental health program for refugee youth
Hasanovic (2009)	Psychosocial assistance to students with posttraumatic stress disorder in primary and secondary schools in post-war Bosnia Herzegovina
Karam (2008)	Effectiveness and specificity of a classroom-based group intervention in children and adolescents exposed to war in Lebanon
Layne (2008)	Effectiveness of a school-based group psychotherapy program for war-exposed adolescents: A randomized controlled trial
Mancini (2019)	A pilot study evaluating a school-based, trauma-focused intervention for immigrant and refugee youth
Ooi (2016)	The efficacy of a group cognitive behavioral therapy for war-affected young migrants living in Australia: A cluster randomized controlled trial
O’Shea (2000)	A school-based mental health service for refugee children
Peltonen (2012)	Effectiveness of school-based intervention in enhancing mental health and social functioning among war-affected children
Rousseau (2009)	Evaluation of a sandplay program for preschoolers in a multi-ethnic neighborhood
Rousseau (2012)	Innovations in practice: A pilot project of school-based intervention integrating drama and language awareness
Saltzman (2001)	Trauma- and grief-focused intervention for adolescents exposed to community violence: Results of a school-based screening and group treatment protocol

Unfortunately, although the strict selection criterion regarding trauma exposure provided clearer decisions and certainty that at least 50% of the assessed sample had experienced at least one type of interpersonal violence, the exclusion of these otherwise relevant studies also meant an omission of some important findings and a restriction of regional diversity in the current systematic review. More specifically, the excluded studies largely assessed war- and flight-related trauma (12/13) and were conducted in a range of different countries, that is, USA (3/13), Canada, Palestinian Territories and Bosnia and Herzegovina (2/13 each), as well as the UK, Australia, Israel and Lebanon (1/13 each), with English-speaking countries again dominating research (8/13). While, similar to the included studies, most excluded studies assessed PTSD (9/13) and depression (7/13) as posttraumatic outcomes, there were also a number focussing on emotional and behavioural problems (5/13). Regrettably, a large number of interventions implemented by teachers (7/13) had to be excluded, as well as all interventions incorporated into the school day (5/13) as opposed to extracurricular sessions. Furthermore, all studies achieving no mitigation of posttraumatic symptoms (4/13) were excluded.

Future research

Due to the current systematic review’s objective and resulting heterogeneity of studies as well as samples included into data extraction and synthesis, a meta-analysis was not feasible. As a result, no conclusions can be drawn regarding the actual effectiveness of school-based interventions for posttraumatic symptoms following interpersonal violence. As shown by the current systematic review, a strict criterion regarding (interpersonal) trauma exposure can moreover lead to the exclusion of a range of relevant intervention studies – in fact, trauma exposure was the criterion most studies were excluded by (see Figure 1). In situations where children and adolescents are exposed to war or community violence, however, interpersonal violence is rarely a singular event but rather goes hand in hand with a myriad of other potentially traumatic experiences. Additionally, in a heterogenous school or classroom setting, diverse experiences of the pupils targeted by the intervention are to be expected. As such, necessary meta-analyses on comparable school-based trauma interventions (e.g. manualised, CBT-based interventions or teacher trainings) could examine populations of children and adolescents who have experienced trauma globally related to war or flight (including e.g. bombings or shelling) or adverse childhood experiences as a whole (including e.g. incarceration or mental health problems of a parent, drug abuse at home), potentially creating more homogenous and comparable samples rather than including the samples based on experiences of interpersonal violence only.

Limitations

In addition to the aforementioned lack of generalisability of the current findings outside the USA, following limitations have to be considered when interpreting the results of this systematic review. First, the database search and selection process were limited to German and English language publications, quite possibly excluding relevant intervention studies in other languages from the current systematic review. Second, despite efforts to minimise publication bias and despite some intervention studies achieving no significant mitigation of posttraumatic outcomes being present in the retroactively excluded studies, a tendency to publish only ‘positive’ and significant results cannot be ruled out. While the current findings indicate benefits of school-based interventions for children and adolescents after complex interpersonal trauma, one should be careful not to overestimate this benefit. Third, while a majority of included studies implemented manualised or standardised interventions, modifications to the interventions were made in some cases according to the needs and local conditions in participating schools, making statements about the benefit of these manualised interventions in their intended form difficult or even impossible. Fourth, 40% of included studies used a single sample pre-post or non-randomised controlled study design, and about one third of RCT-studies did not include a follow-up assessment. Fifth, the comparability of included studies may be limited by the sample compositions themselves (e.g. age range very large or not reported, in part small sample sizes, varying gender proportions). Sixth, the tool used for assessment of methodological quality (MMAT, Hong et al., 2018) was developed with a clinical or medical focus. However, as none of the included studies were medical trials, their methods were not reported with the necessary detail, resulting in many assessments of ‘not enough information available’ especially with regards to RCTs. Consequently, study quality was rated as medium or low for most studies. We nonetheless chose to use the MMAT due to its capacity to assess methodological quality of different study types within the same systematic review. Last, as mentioned above, no meta-analysis was conducted in view of the current review’s objectives and resulting heterogeneity of included studies. However, a systematic review without meta-analysis can neither provide insight about the actual effectiveness of intervention studies nor compare the effectiveness of school-based interventions.

Strengths

Taking into account the limitations, the current systematic review also shows a number of strengths. Most of the included studies used a randomised-controlled design, almost all made an effort to implement manualised or standardised interventions or intervention components. The interventions were generally gender-inclusive and addressed populations with a broad range of interpersonal trauma experiences. The findings show not only a benefit of school-based interventions for a range of posttraumatic outcomes, but also that trained school staff is able to implement these interventions with support of mental health professionals. In summary, the current systematic review adds to existing research and knowledge about the possible benefit of school-based mental health interventions. Previous systematic reviews on school-based interventions had only assessed PTSD as posttraumatic outcome (Rolfsnes & Idsoe, 2011) or included all types of trauma, including non-interpersonal (Rolfsnes & Idsoe, 2011; Yohannan & Carlson, 2019; Zakszeski et al., 2017). Considering the broad range and severity of psychosocial and health consequences of interpersonal violence (e.g. Jimenez et al., 2016; Kien et al., 2018; Larson et al., 2017; Maercker, 2013; Norman et al., 2012), these findings imply not only that school-based interventions may be beneficial for the specific sample of children and adolescents exposed to interpersonal violence, but also that they can be used to address a range of posttraumatic outcomes following interpersonal violence.

Conclusions

The most critical findings of the current systematic review are that (a) school-based interventions can be feasible and beneficial for the mitigation of posttraumatic outcomes in children and adolescents following interpersonal trauma, and (b) trained school personnel supported by mental health professionals are able to implement trauma interventions and trauma-informed practices at school (see Table 6). From these central findings, several conclusions can be drawn regarding practice, policy and research (summary in Table 8). In Practice, research has shown that a number of structural and personal barriers to regular mental health care exist for children and adolescents (e.g. Colucci et al., 2015; Kowalski et al., 2012; Larson et al., 2017; Metzner et al., 2016). Providing mental health care is not the primary role of schools. However, as schools are the place most young people can be reached, the implementation of trauma interventions and especially trauma-informed practices in schools seems to be a promising approach to better connect educational and mental health care systems, supplement regular mental health care services and reduce barriers to care. Trained school staff (e.g. teachers, school counsellors) could thus serve as a first line of contact for pupils who have experienced interpersonal violence. With view to Policy, the implementation of a trauma-informed learning environment or school-based trauma services requires at least stable financing, cooperation between mental health services and schools as well as sufficient knowledge in school staff. Surveys for example in Canada (Weegar & Romano, 2019) and Germany (Ullrich & Zimmermann, 2014) however have shown a lack of knowledge, skills and training regarding trauma and interpersonal violence in teachers. Structures and guidelines to improve teacher training regarding trauma-sensitive practices, enable inter-agency cooperation and to ensure financial support during this process can only be put into place by policymakers. In Research, there is a need for school-based intervention studies from more countries apart from the USA, especially regarding the transferability and feasibility of (long-term) implementation of school-based intervention approaches in diverse school systems worldwide. In view of the large percentage (40%) of studies relying on pre-post or non-randomised designs, more RCT studies are needed to evaluate school-based interventions. Meta-analytic systematic reviews are necessary to assess the effectiveness of school-based interventions for posttraumatic symptoms after interpersonal violence in children and adolescents. However, as shown above, the inclusion of study populations for (meta-analytic) systematic reviews using an overly strict criterion for interpersonal trauma exposure can lead to the exclusion of a multitude of relevant school-based intervention studies. Therefore, future meta-analytic reviews that focus on populations who have either experienced global war-related trauma or adverse childhood experiences may further expand on existing knowledge about possible effects of school-based interventions.

Table 8.

Summary of implications for Practice, Policy and Research.

Implications
Practice	⁃ School-based trauma interventions can supplement regular mental health care for traumatised children and adolescents and reduce barriers to care.⁃ Trained school staff can help to support traumatised children and adolescents.
Policy	⁃ Necessary resources, structures and guidelines must be put into place (e.g. financing, trauma-sensitive teacher training, inter-agency cooperation).
Research	⁃ More school-based intervention studies outside the USA and using RCTs are necessary (e.g. regarding implementation in diverse school systems).⁃ Meta-analyses are necessary to assess the effectiveness of school-based interventions regarding complex interpersonal trauma.⁃ Meta-analyses could focus on children and adolescents generally exposed to war or adverse childhood experience.

Footnotes

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iD

Michelle L-Y Wichmann

Notes

Author Biographies

Michelle Lok-Yan Wichmann (M.Sc.) is a Research Associate and Doctoral Student in the Department of Educational Science and Psychology at the University of Siegen. Her research interests include interpersonal violence and trauma, posttraumatic symptoms in children and adolescents, child protection, intervention and prevention in educational settings, as well as the social-emotional development of children and adolescents.

PD Dr Silke Pawils, Dipl.-Psych., heads the research group ‘Prevention in Children and Adolescents’ at the University Medical Center Hamburg-Eppendorf. In various projects she works on universal and indicated preventive fields in addiction and violence prevention as well as general health promotion in the target group of children and adolescents, in particular those traumatised by interpersonal violence.

Julia Richters (BA) studies educational science (teaching profession) at the University of Siegen. Since 2019, she is a Student Assistant in the Department of Educational Science and Psychology at the University of Siegen and supports research work in the fields of interpersonal violence, posttraumatic symptoms and school-based trauma interventions, among others.

Dr Franka Metzner, Dipl.-Psych., is a Research Associate at the University Medical Center Hamburg-Eppendorf and in the Department of Educational Science and Psychology at the University of Siegen, as well as a Psychotherapist (Behavioural Therapy, in training). Her research interests include posttraumatic symptoms and discrimination experiences in refugee children, school-based trauma interventions, child protection in schools and medical child protection.

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