There’s still a lot to learn about ADHD

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A look at the characteristics of ADHD, typical educational outcomes and how classroom contributions can shape symptoms

Attention deficit hyperactivity disorder (ADHD) is one of the most frequently occurring developmental disabilities, with a recent study (Polanczyk and Rohde, 2007) estimating the disorder’s prevalence to be 5.29 per cent in children and adolescents and 4.4 per cent in adults. The hyperactivity disorder is characterised by three core symptoms: inattention, hyperactivity and impulsivity. These affect both cognitive and behavioural functioning and lead to impairments in both academic and social contexts. The pervasive nature of these symptoms is integral to the diagnosis, with children having to display symptoms in two or more different environments, which typically are home and school, in order to be diagnosed with the disorder.

Individuals with ADHD are also much more likely to have additional disorders, such as conduct disorder, oppositional defiant disorder, anxiety, and mood disorders (Faraone, Biederman and Monuteaux, 2002). Studies have shown that students who start school with attention problems often experience difficulties learning to read which persist throughout school. Reading disabilities also tend to co-occur with ADHD, with estimates of this ranging from 25 to 40 per cent in clinical samples and fifteen to 35 per cent in community samples (Willcutt et al., 2001).

In the long term, ADHD is associated with poorer educational outcomes, such as higher school drop-out rates and fewer years of educational attainment overall. However, despite the significant risk factor that ADHD poses for academic difficulty, there has been little research into the classroom and school contexts that influence both inattentive and hyperactive behaviour and academic achievement in children with ADHD.

While the dominant medical paradigm that has shaped both research and discourse on ADHD emphasises the genetic underpinnings and within-child neuropsychological deficits that contribute to the etiology of the disorder, social constructivists, in contrast, have highlighted the ways that the social context of the child’s environment shapes ADHD symptoms (Prosser, 2008; Wiener, 2007).  An alternative framework is the developmental psychopathology perspective, which attempts to specify the developmental pathways that are associated with hyperactivity and inattention and to predict outcomes of the disorder by looking at the interaction of genetic and environmental risk factors (Johnston and Mash, 2001; Sonuga-Barke, 2005).

To date, research has largely focused on family predictors that contribute to ADHD symptoms, and few studies have considered the influence of teaching practices on the expression of behaviour in school. There is no doubt that the classroom represents an important developmental context for children with ADHD, as it has the potential to influence the academic, social, and behavioural skills that are often impaired in ADHD.

Where teaching practices and surroundings have been considered in studies, they have largely been classroom-based and focused on modifying specific aspects of teaching, rather than examining broad factors that contribute to behaviour and academic achievement. However, by identifying risk and protective factors within the classroom, that contribute to behaviour typically associated with ADHD, we can start to understand the development of the disorder by considering both individual differences and environmental factors within education.

There is also strong evidence that ADHD is hereditary, with family, twin and adoption studies consistently reporting a strong genetic influence on ADHD, with heritability estimates currently standing at 76 per cent (Faraone et al., 2005).

Research to date has also explored several biological and family factors, such as the quality of the home environment and parental psychopathology, with prenatal factors such as prematurity, low birth weight, pregnancy, birth complications, smoking during pregnancy and foetal alcohol exposure showing the most consistent evidence of association with childhood ADHD symptoms.

Following on from this, in a longitudinal study that attempted to track the relative contribution of genetic, prenatal, temperamental, maternal and contextual factors to children’s distractibility and hyperactivity, researchers reported that the quality of observed care giving was a more powerful predictor than early endogenous factors such as biological or temperamental factors (Carlson, Jacobvitz and Sroufe, 1995).

Unlike most studies that use self-report questionnaires, this research observed early parent/child interactions, documenting that maternal intrusiveness at six months and over-stimulating care given at three and a half years predicted hyperactivity in the early elementary years.

In addition, contextual variables such as parent relationship status at birth and emotional support for the parent were both correlated with distractibility and hyperactivity, suggesting that early environmental factors represent important contributing factors to the development of ADHD symptoms. Parent-rated symptoms of child inattention have also been related to psychosocial stressors within the family, such as adversity, marital conflict and maternal psychopathology.

Parents of children diagnosed with ADHD report high levels of family conflict, which may mediate the association between parental psychiatric diagnoses and impairments in children with ADHD (Kepley and Ostrander, 2007). In addition, factors in the family that create an inconsistent, disorganised environment may further impair the child’s functioning (Pliszka, 2007).

However, it is difficult to determine from these studies how the child’s problematic behaviour could be eliciting family conflict or how such issues can actually exacerbate the child’s existing problem behaviour and how these patterns may develop into a negative cycle.

It is also worth considering that many of these studies rely on self-report data, which introduce parents’ biases and expectancies regarding parenting and may not clearly reflect parent/child dynamics at home. Moving forward, we are now beginning to see more observational studies that assess children’s functioning within the home environment in comparison to their behaviour in different settings. This will help to elucidate the social context for ADHD behaviour and distinguish between motivational and cognitive features of the disorder.

There is certainly still a lot to learn, but over the coming years our knowledge and understanding of the disorder is set to grow substantially which will help to create better futures for those with ADHD and those at risk of developing it.

Further information

Louise Deault is an expert in child psychiatry and human development at McGill University, Montreal. This article is adapted from her article in The International Handbook of Psychology in Education:
http://books.emeraldinsight.com

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