ADHD and reading disorder

Abstract

This chapter provides an overview of current knowledge regarding the frequency, implications, and aetiology of comorbidity between ADHD and reading disorder (RD), a common childhood disorder that is defined by significant underachievement in reading. Results from community studies indicate that 20–50% of individuals with ADHD also meet criteria for RD, and the presence of comorbid RD is associated with increased functional impairment and less positive long-term outcomes. Family and twin studies indicate that RD and ADHD are both significantly familial and heritable, and multivariate analyses indicate that nearly all of the phenotypic covariance between RD and ADHD is due to shared genetic influences that are associated with slower and more variable cognitive processing speed. Key future directions include studies that incorporate a broader range of measures of reading and more sophisticated neuropsychological and neuroimaging phenotypes, along with studies of the treatment implications of comorbidity between ADHD and RD.