Childhood maltreatment is a prevalent risk factor associated with long-term morbidity and mortality, mental health problems, and adult violence[1-2]. In 2014 alone, 6.6 million children in the U.S. were involved in referrals where there was alleged maltreatment, including 702,000 victims of child abuse and neglect[3]. Psychiatric morbidity attributed to early maltreatment is extensive and often severe[4-6]. Recent research reveals associations between adverse childhood experiences including physical abuse and neglect with ADHD[7-8]. ADHD is a psychiatric disorder with childhood onset (<12), characterised by its dimensions of hyperactivity/impulsivity and inattentiveness[9], and its high heritability is well documented[10]. ADHD is also associated with problems related to executive functioning, including the ability to self-regulate[11].

Quality of parental care, including harsh parenting is a risk factor for the development of behavioural problems early in life[12]. Parenting and family factors have been recognised to affect the course of ADHD, and the development of comorbidity. In addition, parents of children with ADHD report significantly more stressful and dysfunctional parent-child interactions than do parents of children without ADHD[13].

Studies examining the relationship between ADHD and maltreatment have reported significant associations[7-8, 14-15], however most of these studies have used cross-sectional designs, limiting any directional or causal interpretation. Most also lack essential confounders such as family-level and psychiatric factors, and unexplained genetic variance. Early maltreatment as a distinct risk factor for ADHD has not been effectively examined. Moreover, the role of parenting behaviours and early maltreatment with ADHD has not been systematically studied using well-characterised population data.

Our aim is to the examine the role of parenting practices, with an emphasis on maladaptive parenting and early child abuse, with the developmental course of ADHD symptoms and its symptom trajectories from early childhood through adolescence, and associated adverse outcomes. We aim to perform a systematic evaluation of the role of these exposures at the population level using representative longitudinal data.

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3. U.S. Department of Health & Human Services AfCaF, Administration on Children, Youth and Families, Children’s Bureau., ed2016. Child Maltreatment 2014.
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