Estimates of the prevalence of attention-deficit/hyperactivity disorder (ADHD) vary widely within and between countries. The UK National Institute for Health and Care Excellence (NICE) have estimated that around 5% of school-aged children and adolescents meet the DSM-IV diagnostic criteria for ADHD, equivalent to 366,000 children and adolescents in England and Wales . Attention-deficit/hyperactivity disorder is a debilitating mental health disorder, which is marked by symptoms of inattention, overactivity and impulsiveness that have an early onset, and are age inappropriate, persistent and pervasive . It affects children over their school years and into adulthood  and is associated with a number of impairments that impinge on a range of social and health care systems (education, criminal justice, mental health, social services, and so on) . Those with ADHD are at increased risk of delinquency, criminality, educational failure and mental illness [5, 6]. Treatment for ADHD typically begins during the middle school years  and multimodal approaches are recommended . Stimulant and nonstimulant [7, 8] medications are considered the most efficacious treatments and are recommended. However, these have a number of limitations [9–12], including reported side effects [11, 13, 14] and can give rise to parental concerns about the use of medication for behavioural control . Furthermore, medication on its own might not improve other outcomes, such as social and academic functioning . Nonpharmacological treatments, such as classroom-based behaviour modification or parent-training programmes can also be valuable but appear not to provide the same control of ADHD symptoms offered by pharmacological treatments .
To optimize the effects of nonpharmacological therapies, early intervention approaches implemented during the preschool period have been proposed . Such proposals are consistent with the fact that, even though most ADHD cases are first formally diagnosed and treated in middle childhood, ADHD often has its roots in the preschool period [19–21]. In fact, while significant levels of preschool-type ADHD symptoms may not always signal the early ‘onset’ of impairment, numbers of referrals of ADHD before the age of 5 years are growing [1, 5, 22].
A number of parent-training programmes have been developed to target preschool ADHD [23–25]. The New Forest Parenting Programme (NFPP) is a home-based approach designed specifically to target the core symptoms of ADHD in preschool children. It is delivered on a one-to-one basis . It has been shown in randomized controlled trials (RCTs) to substantially reduce levels of ADHD symptoms and related problems, such as oppositional defiant disorder (ODD) [27, 28]. A second approach, the Incredible Years (IY) programme, was originally designed to target children’s oppositional and noncompliant behaviour. It consists of a suite of programmes for parents, children and teachers. While originally, and still mainly, delivered to groups of parents, children and teachers, there is now also a home-coaching model for the parent programme. These programmes, both individual and in various combinations, have been demonstrated to reduce children’s noncompliance and troublesome behaviour and increase positive behaviour . It has also produced generally positive effects on these outcomes with preschool children, including those with or at risk of ADHD [29–32]. A recent adaptation specifically for children with ADHD has shown benefits in terms of parents’ ratings of ADHD symptom reduction [33–37]. The IY programme has been recommended for use with preschool ADHD children in influential guidelines, such as those published by NICE , partly on the basis that its group-based nature is thought to be a cost-effective therapy .
Despite positive findings from RCTs, there are many barriers to effective implementation of these treatments in everyday practice [40–42], especially with regard to individuals and families traditionally seen as hard to engage and treat. Such factors as the presence of parental mental health problems, the existence of additional child comorbid conditions, cognitive and language problems and the presence of adverse environmental factors need to be addressed if preschool parenting packages are likely to work with those most in need of help. Knowing how to access and engage ‘at-risk’ and ‘hard-to-reach’ children and their families, who may be living in difficult circumstances, is therefore central to the development of an effective early detection and intervention strategy. Previous research indicates that when access is made available, the outcomes for ‘hard-to-reach’ families attending the IY parent programme are as good as those less disadvantaged .
The Comparison of Preschool Parenting Interventions (COPPI) trial is the fifth and final project in the 5-year Programme for Early Detection and Intervention for ADHD (PEDIA). This programme of research, funded by the National Institute for Health Research, is being carried out at the University of Southampton in collaboration with Solent NHS Trust, and at two other centres: the University of Nottingham in collaboration with Nottingham City Care and Nottingham County Health Partnerships and the North Staffordshire Combined Healthcare NHS Trust.
Using an evidence-driven approach, the NFPP has been recently adapted to address the specific needs of ‘hard-to-reach’ and ‘difficult-to-treat’ preschool children with ADHD and their families (F McEwan et al., unpublished work) . This has involved extending it from an 8- to a 12-week programme with the inclusion of specific modules to address such problems as parental mental health problems and child comorbid developmental conditions. In this trial, we will evaluate the effectiveness and cost-effectiveness of the adapted-NFPP against IY and treatment as usual (TAU) in a multicentre RCT.
Aims and objectives
The overall aim of this study is to conduct a large-scale multicentre RCT of the efficacy of the adapted-NFPP by comparing it with (i) a TAU group and (ii) a generic parenting package recommended by NICE (IY) in a sample enriched for potentially hard-to-reach and treat children.
The key objectives are to test whether, for individuals with preschool-type ADHD problems, the adapted-NFPP produces statistically greater beneficial effects in terms of core symptoms of ADHD and other secondary outcomes (general child behaviour problems and parental mental health); to determine whether outcomes are moderated by factors that might be predictive of long-term burden and other potentially important moderators, including genetic factors; to determine whether effects are mediated by (a) improved parenting and (b) improved neuropsychological function; and to determine whether the adapted-NFPP is more cost-effective.
The main research questions are:
Does the adapted-NFPP produce statistically greater reductions in ADHD symptoms compared with a TAU group and standard IY 12-week parenting programme in a sample of individuals with preschool-type ADHD problems enriched for ‘hard-to-reach’ and potentially treatment-resistant preschool children?
Do these effects extend to other problems, such as child conduct problems?
Do they generalize from home to educational settings?
Are these effects moderated by (i) factors that might be predictive of long-term burden as well as other putative barriers to treatment efficacy and (ii) genetic factors?
Are these effects mediated by (a) improved parenting and (b) improved neuropsychological function?
Do benefits persist in the longer term (for example, 6 months after treatment)?
Is the adapted-NFPP cost-effective relative to IY in this enriched sample over a 6-month period and does the added value of adapted-NFPP outweigh any additional costs of treatment delivery?