Sally J. Wadsworth, Senior Research Associate
Ph.D. 1994, University of Colorado

My CLDRC research interests center around the use of behavioral genetic methods to study individual differences in cognitive abilities and disabilities, and their relations with academic achievement and behavioral problems. Collaborations with other Center investigators have focused on assessment of the genetic and environmental bases of Reading Disability, ADHD and their comorbidity. In an exciting extension of this work, we are conducting a longitudinal follow-up of CLDRC participants as part of a new component of the Center (Project VI), a continuation of the Longitudinal Twin Study of Reading Disability (LTSRD, DC005190; These data will be combined with follow-up data previously collected, as well as with data from the International Longitudinal Twin Studies of Early Reading Development (ILTS; R.K. Olson, E.G. Willcutt, PIs; HD0038526;, recently funded to extend testing of a population sample of twins through ninth grade (HD068728). This will facilitate more powerful tests of the developmental etiologies of reading/writing difficulties, ADHD and their comorbidity, as well as factors that may influence positive or negative outcomes.

Other related research includes collaboration with Center co-investigators to conduct a genome-wide screen for quantitative trait loci that increase risk for reading disability and ADHD using data from the largest sample of siblings with RD ascertained to date (Erik Willcutt, P.I.; HD047264).

The long-term goal of the combined work of these projects is to identify genetic and environmental risk and protective factors that predispose children to reading and writing difficulties and academic success versus failure, thereby informing instruction and remediation approaches.

My interest in reading ability and it’s interrelations with cognitive abilities and academic achievement over time is reflected further in my work with the Colorado Adoption Project (HD010333; S. J. Wadsworth, PI;, now in it’s fourth decade, exploring the broader relations between lifespan development, cognitive aging and health.

PubMed list of recent publications

Representative Publications:

Wadsworth, S.J., Corley, R.P., Hewitt, J.K., Plomin, R. & DeFries, J.C. (2002).  Reading performance at 7, 12 and 16 years of age in the Colorado Adoption Project: Parent-offspring analyses.  Journal of Child Psychology and Psychiatry, 43, 769-774.

Wadsworth, S.J. & DeFries, J.C. (2005). Genetic etiology of reading difficulties in boys and girls. Twin Research, 8, 594-601.

Wadsworth, S.J., DeFries, J.C., Olson, R.K., & Willcutt, E.G. (2007). Colorado Longitudinal Twin Study of Reading Disability, Annals of Dyslexia, 57, 139-160.

Willcutt, E. G., Betjemann, R. S., Pennington, B. F., Olson, R. K., DeFries, J. C., & Wadsworth, S. J. (2007). Longitudinal study of reading disability and attention-deficit/hyperactivity disorder: Implications for education. Mind, Brain, and Education, 4, 181-192.

Betjemann, R.S., Willcutt, E.G., Olson, R.K., Keenan, J.M., DeFries, J.C., & Wadsworth, S.J. (2007). Word reading and reading comprehension: stability, overlap and independence. Reading and Writing, 21, 539-558.

Haworth, C.M., Wright, M.J., Luciano, M., Martin, N.G., de Geus, E.J., van Beijsterveldt, C.E., Bartels, M., Posthuma,D.,  Boomsma, D.I., Davis, O.S., Kovas,Y., Corley, R.P., DeFries, J.C., Hewitt, J.K., Olson, R.K., Rhea, S.A., Wadsworth, S.J., Iacono, W.G., McGue, M., Thompson, L.A., Hart, S.A., Petrill, S.A., Lubinski, D., Plomin, R. (2010). The heritability of general cognitive ability increases linearly from childhood to young adulthood. Molecular Psychiatry, 15, 1112-20. PMCID: PMC2889158

Wadsworth, S.J., Olson, R.K., & DeFries, J.C. (2010).  Differential Genetic Etiology of Reading Difficulties as a Function of IQ: An Update. Behavior Genetics, 40, 751-758. NIHMSID # 180527

Astrom, R.L., Wadsworth, S.J., Olson, R.K., Willcutt, E.G., & DeFries, J.C. (2011). DeFries-Fulker analysis of longitudinal reading performance data from twin pairs ascertained for reading difficulties and from their nontwin siblings. Behavior Genetics, 41, 660-667. PMCID: PMC3085049

Wadsworth, S.J., Olson, R.K., Willcutt, E.G., & DeFries, J.C. (2012). Multiple Regression Analysis of Reading Performance Data from Twin Pairs with Reading Difficulties and Non-twin Siblings: TheAugmented Model.  Twin Research and Human Genetics, 15(1):116-9. PMCID: PMC3398740.


Sally Wadsworth







Sally Wadsworth

Ph.D. 1994
University of Colorado

447 UCB
Boulder, CO 80309-0345
phone: 303-492-6795
fax: 303-492-8063