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. 2017 Jun;58(6):719-727.
doi: 10.1111/jcpp.12691. Epub 2017 Feb 8.

Explaining the sex difference in dyslexia

Anne B Arnett  1 , Bruce F Pennington  2 , Robin L Peterson  3   4 , Erik G Willcutt  5 , John C DeFries  5 , Richard K Olson  5
Affiliations

Explaining the sex difference in dyslexia

Anne B Arnett et al. J Child Psychol Psychiatry. 2017 Jun.

Abstract

Background: Males are diagnosed with dyslexia more frequently than females, even in epidemiological samples. This may be explained by greater variance in males' reading performance.

Methods: We expand on previous research by rigorously testing the variance difference theory, and testing for mediation of the sex difference by cognitive correlates. We developed an analytic framework that can be applied to group differences in any psychiatric disorder.

Results: Males' overrepresentation in the low performance tail of the reading distribution was accounted for by mean and variance differences across sex. There was no sex difference at the high performance tail. Processing speed (PS) and inhibitory control partially mediated the sex difference. Verbal reasoning emerged as a strength in males.

Conclusions: Our results complement a previous finding that PS partially mediates the sex difference in symptoms of attention deficit/hyperactivity disorder (ADHD), and helps explain the sex difference in both dyslexia and ADHD and their comorbidity.

Keywords: Reading; dyslexia; inhibition; processing speed; sex difference; verbal reasoning.

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Conflict of interest statement

The authors do not have any conflicts of interest.

Figures

Figure 1
Figure 1
Framework for Analyzing Group Differences
Figure 2
Figure 2
Reading skill distributions by sex. X-axis values are mean z-scores for the reading composite.
Figure 3
Figure 3
Schematic of the Mean Difference and Variance Difference Models.
Figure 4
Figure 4
Mediation of the Sex Difference in Reading by cognitive endophenotypes. PS = processing speed; INH=inhibition, VR=verbal reasoning. (A) Total effect of sex on reading. (B) Direct and indirect effects of sex on reading. Values are standardized beta coefficients. *p<.05, **p<.01, ***p<.001.
See this image and copyright information in PMC

References

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