Elsevier Logo Attention Deficit Hyperactivity Disorder (ADHD) and developmental reading disability (RD) are complex childhood disorders that apparently occur together. So, when a child is experiencing trouble with reading, symptoms of ADHD are probably present too. Though the reason for this link is presumably under wraps, it can result in slow processing speed and the brain will take longer to make sense of the received information. A latest study asserts that both the conditions ADHD and RD have common genetic influences.

In order to conduct the study, scientists evaluated 457 pairs of twins from the Colorado Learning Disabilities Research Center (CLDRC) twin study. Groups of participants with and without RD as well as ADHD were thoroughly analyzed with the help of various tests to calculate general cognitive ability, processing speed, reading and language skills. The results from pairs of twins within those groups were compared for ascertaining the genetic causes of any associations. The investigation helped experts distinguish between genetic and environmental influences on the participants’ cognitive abilities.

Both RD and ADHD are complex disorders allegedly influenced by many factors. While ADHD is related with the ability of inhibiting responses to stimuli, reading disabilities have been linked with various weaknesses in language and memory. It appears that RD as well as ADHD slow processing speed. A participant with one of the disorders was probably more likely to show symptoms of the other. Dr. Erik Willcutt and colleagues suggest that processing efficiency can be a crucial marker to find the connection between both the disorders.

The study is published in the latest issue of Cortex.