The research question is: Can the research recommend better ways for social care and health services to work work together to help adoptive and foster families? Can a therapy called DDP improve the mental health of 5-12 year old fostered or adopted children? Is DDP worth the commitment families need to give to it - and the extra cost to the services that deliver it? More than half of adopted or fostered children in the UK have mental health problems including ADHD (i.e. hyperactivity, impulsive behaviour and poor concentration), antisocial behaviour and problems with relationships. Abused and neglected children are more likely than others to have problems in school, become homeless, get involved in crime and even die young (e.g. from suicide), yet there are no fully tested treatments for such complex mental health problems. This is a huge problem because early treatment could greatly improve children's life chances - and reduce strain on health and social care budgets.

There is a Dyadic Developmental Psychotherapy (DDP) a parent-child therapy that takes around 20 sessions and focusses on "Playfulness, Acceptance, Curiosity and Empathy". There is not yet available really good evidence for or against it: many UK therapists like DDP, but it is a big commitment for families: once a week for about six months children will need time off school, the parents will need time off work - and this can be hard to explain to school friends, colleagues and bosses. Research team doesn't just need to know if DDP improves children's mental health - they also need to know if the commitment needed is worth it for families and whether the costs to services outweigh the benefits.

In PHASE 1 the research team will find out whether DDP can work smoothly in the three different settings where it is usually delivered: the NHS, Social Care and Private Practice. Many abused children need other medical and psychiatric support so, the research will assess whether children can get any additional assessments or referrals they may need .

In PHASE 2, the research team plans to find out if it is practically possible to run a high quality trial of DDP. This phase will involve 60 families to find out if they are happy to take part (whether offered DDP or usual services). If all goes to plan, these 60 families will contribute to the final results, along with the 180 families involved in the next PHASE 3 when the research team will test whether DDP is better than usual services and, if it is, whether the improvements in child mental health outweigh the costs.

What impact will the research have? This study will make recommendations about how services should work together to help abused and neglected children and their families. If the researcher team finds that DDP is worth the time and money, it could improve the mental health of abused and neglected children across the world.

Abused and neglected children are at extremely high lifetime risk of psychiatric disorder placing a huge burden on health/social care services and society. Virtually all 92,000 children adopted or fostered in the UK have suffered abuse or neglect, therefore risking profoundly negative outcomes in important areas of development including problematic social relationships, academic underachievement and involvement in crime. These disadvantages can lead to negative spirals of poor health and social inequality. Early intervention can greatly improve their life chances, yet there are no adequate psychosocial treatment strategies or care pathways to address the needs of maltreated children. Psychiatric problems of maltreated children are characterised by complexity. They have experienced extreme environmental risk and are at higher genetic risk than peers. Many also struggle to develop and maintain healthy family relationships. Neurodevelopmental disorders such as Attention Deficit/Hyperactivity Disorder (ADHD) and Autism often co-exist with disorders arising from the abuse and neglect such as Conduct Disorder, Attachment Disorders and Post Traumatic Stress Disorder (PTSD) with devastating consequences for lifelong mental health and development. To reflect this complexity, research team uses the overarching term Maltreatment-Associated Psychiatric Problems (MAPP).

The proposed project is a three-phase development and exploratory trial of Clinical and cost-effectiveness of Dyadic Developmental Psychotherapy (DDP) for abused and neglected children with MAPP and their parents compared to Service as Usual (SAU). The data will be collected in 3 phase trial, through a mixture of qualitative and quantitative methods.

Phase 1 Months 1-9 (9 months)

The first phase will focus on intervention and context optimisation that will take place in 3 sites, each representing one of the UK DDP service delivery contexts: NHS, Social Services and Private Practice. The research questions will be addressed through 24-36 qualitative interviews, and focus groups as well as review meetings at each site, with practitioners and managers involved in delivery of DDP and SAU. The research team will require input from the services practitioners and managers but also Young Peoples' Advisory Groups (YPAG) and Patient, Public, Commissioner Involvement (PPCI) groups.

Phase 2 Months 10-26 (17 months)

To examine the research questions, and minimise bias, the proposed design is a single-blind randomised controlled trial, with two-groups. The aim of this phase will be to respond to research questions such as what are recruitment and retention rates over 6 months; are the trial assessments and interventions acceptable to parents and professionals; are there functional data collection systems enabling future cost effectiveness analysis. This phase will also assess fidelity to the DDP model and whether the care pathways to CAMHS are maintained throughout.

The research team will aim to recruit around 60 families. The potential participants will be identified and approached by their usual service provider. The usual service research administrator will ensure eligible families receive the study participant information leaflet to learn about the study. Once the interest of the family to take part in the trial is confirmed, a research nurse will contact interested families 24 hours later, to discuss the study further and seek consent. Families that confirm their willingness to participate will be invited for two study visits one at baseline, shortly after joining study and second visit after 12 months.

On completion of the baseline data collection, consenting families will be individually randomised 1:1 to DDP or SAU, stratified by site. Individuals who consent to take part will have an equal chance of being randomised to either group. One group will be included in the DDP intervention. The second group will take part in the Services as Usual. The research assistant with responsibility for collecting the data will not know which group participants have been allocated to until the end of the study. The intervention will be delivered by the participant's usual health care team.

Beside the randomised controlled trial, the data will be collected through qualitative research activities to explore social context supporting/hindering child mental health, optimising the contexts of, and processes for, DDP delivery.

Process evaluation

Qualitative work in phase 2 has three main aims:

1. To keep abreast of issues and themes uncovered in Phase 1 in the three feasibility trial sites, to ensure ongoing compliance with guidelines for safe DDP delivery and to explore the social context supporting/hindering child mental health in each site including drivers and barriers to optimal DDP/SAU delivery. 6-10 interviews/focus groups will be conducted with therapists, managers and families across the sites.
2. To explore the same topics from Phase 1 in the seven putative Phase 3 trial sites - optimising the contexts of, and processes for, DDP delivery in those sites and examining compliance with the DDP delivery guidelines established in Phase 1. 18-26 interviews/focus groups will be conducted across the sites.
3. To allow selection of 2-4 additional sites for Phase 3. The number of additional sites required for Phase 3 will be decided based on Phase 2 conversion rates from eligible to consented families and on statistical power considerations based on the standard deviation, in Phase 2, of our principle outcome measure.

Phase 2 will also adopt case study methodology to focus more specifically on the impact of DDP and SAU. The research team will learn through a more in-depth investigation (individual interviews) about participant experience of DDP/SAU and of journeys through service landscapes from the perspectives of the family, therapists, and other key stakeholders involved in the treatment of and care pathways. A small selection of families (2-3 families) will be invited to take part.

Phase 3 Months 27-53 (27 month RCT; (6 month analysis/write-up).

The third phase will continue as a single-blind individually randomised controlled superiority definitive trial. The aim of this phase will be to examine the clinical and cost-effectiveness of DDP for improving child mental health, compared to SAU. The principle outcome will be child's mental health at 12 months post randomisation. The research team will aim to recruit additional 180 families, including phase 2. The study population, interventions, randomisation, data collection, measures, model fidelity and procedures will be as described for Phase 2 unless findings from the process evaluation suggest modifications.

Qualitative evaluation (process evaluation) will continue at the same intensity as Phase 2, with a similar number of interviews/focus groups (24-36 across all sites), to explore delivery drivers/barriers in each service context. The case studies will continue, involving a further 10-12 interviews, to track development over time. The PPCI group and YPAG will have a crucial role in the Process Evaluation, during this phase, in reviewing the qualitative findings with the Process Evaluation Team (PET) and considering how these findings pragmatically feed into future service delivery. Whether or not DDP is eventually found to be cost-effective over services as usual, the process evaluation will yield important information about how mental health services can be safely delivered for maltreated children in different services contexts (i.e. NHS CAMHS, Social Care and Private Practice).

Inclusion Criteria:

• Adoptive or permanent foster parents with children aged 5-12 years with symptoms of MAPP or co-occurring mental health conditions and non-psychotherapeutic treatments

Exclusion Criteria:

• Families, otherwise eligible, deemed by therapists as not ready for DDP (usually where therapists have concerns about the ability of carers/parents to create a safe/ nurturing enough environment within which DDP can operate)
• Children currently having another psychotherapy