Children and young people witnessing domestic violence and abuse (DVA) can be affected negatively in terms of their psychological, emotional, and social development.

Adverse events in childhood are known to be harmful to a young persons development and influence their life course, and therefore is a significant public health issue.

The aim of this rapid review is to highlight the evidence on effective interventions (and any relevant cost-effectiveness evidence) focusing on reducing the harms for children and young people who have been exposed to DVA.

Twenty-five studies were identified along with three guidance documents from the Welsh Government and the National Institute for Health and Care Excellence (NICE) in the UK. Twenty papers from nineteen studies reported the effectiveness of a wide range of interventions to support children and young people who have witnessed DVA. Most studies found meaningful differences in behaviour following an intervention. However, some studies did not find any differences between the intervention and control groups following an intervention to reduce the negative effects of witnessing DVA.

An included cost-effectiveness analysis suggested that for behavioural outcomes, a psychoeducational intervention delivered to parent and child in parallel is likely to be cost- effective among the interventions they compared. Two further full economic evaluation studies determined the cost-effectiveness of cognitive behavioural therapy interventions to support children and young people who have been exposed to DVA.

Policy and practice implications: Economic evaluations have found preliminary evidence that cognitive therapy is a cost-effective intervention to treat children and adolescents with PTSD. Future interventions should be co-produced with relevant stakeholders and patient and public members (including children and young people).

There is a need for larger, well conducted, pragmatic randomised controlled trials with longer follow-up periods.

Funding statement The Bangor Institute for Medical and Health Research was funded for this work by the Health and Care Research Wales Evidence Centre, itself funded by Health and Care Research Wales on behalf of Welsh Government.

What is a Rapid Review?Our rapid reviews (RR) use a variation of the systematic review (SR) approach, abbreviating or omitting some components to generate the evidence to inform stakeholders promptly whilst maintaining attention to bias. They follow the methodological recommendations and minimum standards for conducting and reporting rapid reviews, including a structured protocol, systematic search, screening, data extraction, critical appraisal, and evidence synthesis to answer a specific question and identify key research gaps. They take 1- 2 months, depending on the breadth and complexity of the research topic/ question(s), extent of the evidence base, and type of analysis required for synthesis.

Who is this summary for?This Rapid Review was conducted as part of the Health and Care Research Wales Evidence Centre Work Programme. The above question was suggested by members of the Communities and Tackling Poverty Group, Welsh Government, and a public representative for the Health and Care Research Wales Evidence Centre. The findings of the Review will inform the Violence against Women, Domestic Abuse and Sexual Violence (VAWDASV) National Partnership Board’s Children and Young Persons working group.

Background / Aim of Rapid Review Children and young people witnessing domestic violence and abuse (DVA) can be affected negatively in terms of their psychological, emotional, and social development (An et al., 2017; Anderson, 2017). Adverse events in childhood (ACEs) are known to be harmful to a young person’s development and influence their life course (Campbell et al., 2016; Edwards, 2022; Lester et al., 2020), and therefore is a significant public health issue (Bellis et al., 2019). The long shadow cast by domestic abuse can influence the prospects and potential of individuals over the life course and beyond into future generations (Bellis et al., 2019; Edwards and McIntosh, 2019; Hardcastle et al., 2018; Hughes et al., 2021; Welsh Government, 2016a).

The aim of this RR is to highlight the evidence on effective interventions (and any relevant cost- effectiveness evidence) focusing on reducing the harms for children and young people who have been exposed to DVA. The review question was: What is the effectiveness and cost-effectiveness of interventions in reducing the harms for children and young people who have been exposed to domestic violence or abuse? As part of an initial search for secondary evidence, a mixed method SR by Howarth et al (2016) was identified as a suitable basis upon which to build this RR. The Howarth et al (2016) SR was funded by the National Institute for Health Research (NIHR) and conducted in England (Howarth et al., 2016). This SR was specifically chosen because it included some economic evidence and reported evidence based on the type of domestic abuse interventions for children and young people. This RR builds upon Howarth et al (2016) by updating the evidence to include more recent studies.

Key Findings Twenty-five studies were identified along with three guidance documents from the Welsh Government and the National Institute for Health and Care Excellence (NICE) in the UK.

Effectiveness of interventions for those exposed to domestic violence and abuse Twenty peer-reviewed papers from nineteen studies reported the effectiveness of a wide range of interventions to support children and young people who have witnessed DVA. Interventions included advocacy services, psychoeducation, Cognitive Behaviour Therapy, play therapy and parenting skills training. Most studies found meaningful differences in behaviour following an intervention. However, some studies did not find any differences between the intervention and control groups following an intervention to reduce the negative effects of witnessing DVA.

Cost-effectiveness of interventions for those exposed to domestic violence and abuse A cost-effectiveness analysis by Howarth et al (2016) suggested that for behavioural outcomes, a psychoeducational intervention delivered to parent and child in parallel is likely to be cost-effective among the interventions that they compared if willingness to pay was approximately £8000 (ICER = 3722 per Standard Mean Difference (SMD). Two further full economic evaluation studies determined the cost-effectiveness of CBT interventions to support children and young people who have been exposed to DVA (Aas et al., 2019; Shearer et al., 2018). Both the Aas et al (2019) and the Shearer et al (2018) interventions were deemed cost-effective alternatives relative to the control groups. Both studies were undertaken from health service and personal social services perspectives (although the authors of one of the studies did not explicitly state their perspective. Future studies may need to broaden their perspectives to consider wider costs to society (Edwards and McIntosh, 2019).

Best quality evidence The best available economic evidence found in this the RR were the full economic evaluation studies that included both effectiveness and cost effectiveness elements (Aas et al., 2019; Shearer et al., 2018). The best quality evidence from the remaining 17 intervention studies reporting clinical effectiveness (which did not include full economic evaluations) were those that followed strict RCT methodology and subsequently scored well in our critical appraisal. All clinical effectiveness studies were deemed to be of moderate to high quality.

Policy Implications

Economic evaluations have found preliminary evidence that cognitive therapy is a cost- effective intervention to treat children and adolescents with PTSD.

Future interventions should be co-produced with relevant stakeholders and patient and public members (including children and young people).

Research Implications

There is a need for larger, well conducted, pragmatic RCTs with longer follow-up periods. Robust full health economic evaluations for new and complex interventions in this area could include economic modelling once a solid evidence base exists.

Information provided from the costing studies may be useful to inform future economic evaluations of interventions to support children and young people who have witnessed domestic abuse as they detail the key resources used for interventions.

A wider societal perspective able to capture a broader set of costs and benefits, for example, possible parent productivity losses, warrants further consideration.

Strength of Evidence All included studies were controlled trials, with most being RCTs. Certainty in the findings were moderate to low as most of the included studies had short time horizons and small sample sizes. Greater confidence in the findings would require a more robust evidence base.

The authors have declared no competing interest.

The Bangor Institute for Medical and Health Research was funded for this work by the Health and Care Research Wales Evidence Centre, itself funded by Health and Care Research Wales on behalf of Welsh Government

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All data produced in the present study are available upon reasonable request to the authors