Understanding early causal pathways in ADHD: can early-emerging atypicalities in activity and affect cause later-emerging difficulties in attention?

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Attention Deficit Hyperactivity Disorder (ADHD) is a clinical disorder that affects attention and concentration in up to 5% of UK children. ADHD can be associated with mental health difficulties and poor quality of life in adulthood, making it important to identify new support strategies. Although the condition tends only to be diagnosed in school-aged children, most of the factors that increase the likelihood of a child developing ADHD are present from birth. The aim of our research is to study the developmental processes that cause ADHD to emerge. We aim to study how early-emerging behavioural changes, detectable as early as infancy, can disrupt subsequent development in other areas. We think this can lead to developmental cascades in which patterns of symptoms become progressively more complex over time. Our long-term aim is to improve our ability to identify and intervene early in the development of ADHD, via early interventions targeted at key cascading developmental mechanisms. To do this we study infants with a family history of ADHD, and we track them longitudinally from birth through to later childhood. In our earlier work we and others have shown that infants later diagnosed with ADHD show two profiles. First, they often have a higher level of physical activity. Second, they can be more reactive and have more negative moods. Importantly, our research also suggested that the changes in attention and concentration that impact school attainment do not emerge until later in development. In this study we ask whether these early-emerging differences in activity and negative mood contribute to later-emerging differences in attention through affecting how much a child can practice their concentration skills. To test this, we will use state-of-the-art methods to measure fine-grained behaviours and brain activity during children's everyday interactions. We will look at how children generate opportunities to concentrate on things through how they interact with objects and people around them. We will also look at how these interactions are disrupted by activity and negative mood in children developing ADHD. First (Aim 1), we will use wearable brain imaging and motion tracking to study 150 toddlers in our ToddlerLab, a new facility optimised for naturalistic toddler imaging. We will measure how activity and negative moods 'interrupt' real-world attention episodes and attentive brain states. By repeating these assessments at 10, 14 and 24 months we will test whether this weakens key attention networks over time. Separately, with our pre-existing cohort of 300 infants with a family history of ASD/ADHD, we will test how the same attentive brain states relate to ADHD symptoms at 6 to 10 years. Second (Aim 2), we will collect day-long home recordings using cameras, microphones and autonomic monitors worn by children and their parents. We will measure how toddlers' increased activity and negative mood can prevent shared parent-child attention states from developing; and how disrupted shared parent-child attention states affect long-term development. Again, by repeating these assessments at three timepoints we will test how these effects emerge over time; and in our pre-existing cohort, we shall test how the same shared attention states during infancy relate to ADHD outcomes at 6 to 10 years. Finally (Aim 3), we shall run an experimental intervention to test whether giving 'live', time-sensitive real-time feedback to parents can break the loop between increased child activity/negative moods and decreased child attention. In particular, we will investigate whether it is possible to help parents to support their child's emerging attention by focusing on timing of when parents give prompts to their child. Taken together our work is designed to test a new mechanistic model for understanding how ADHD symptoms emerge.