a1 Department of Psychology, Florida State University, Tallahassee, Florida, United States of America. email@example.com
Asurge in the search for endophenotypes for psychiatric disorders has occurred in the past several years. An important criterion of an endophenotype is that it is heritable. Two of the most widely used executive cognitive functioning measures are the Wisconsin Card Sorting Test (WCST) and the Stroop Color-Word Test. Each has been considered as a possible endophenotype. However, research on the heritability of each of these measures is sparse, and in the case of the WCST, mixed. As part of a pilot twin study examining cognitive functioning and personality in adults, the WCST and the Stroop were administered to 80 monozygotic and 29 dizygotic twin pairs screened for absence of neurological disease and head injury. Results replicated and extended previous findings for moderate heritability of Stroop performance. However, the WCST showed little evidence of genetic influence, suggesting that it might not meet one of the criteria for an endophenotype.
(Received August 24 2007)
(Accepted September 13 2007)
c1 Address for correspondence: Dr Jeanette Taylor, Florida State University, Department of Psychology, PO Box 3061270, Tallahassee, FL 32306-1270.