For reasons that are unclear, males are diagnosed with dyslexia more often than females. Researchers have now found that this may be due to males' lower average and more variable reading performance relative to females'.

The investigators also found that differences in processing speed-how quickly one can process information and perform cognitive tasks-may help explain sex differences in both dyslexia and attention deficit/hyperactivity disorder.

"The fact that greater variability in males' processing speed partly explains the sex difference in both dyslexia and attention deficit/hyperactivity disorder is very exciting, as it may prove to be a crucial clue in understanding brain differences that lead to the high rate of comorbidity between those two disorders," said Dr. Anne Arnett, lead author of the Journal of Child Psychology and Psychiatry study.

Article: Explaining the sex difference in dyslexia, Anne B. Arnett, Bruce F. Pennington, Robin L. Peterson, Erik G. Willcutt, John C. DeFries and Richard K. Olson, Journal of Child Psychology and Psychiatry, doi: 10.1111/jcpp.12691, published online 8 February 2017.