THE WISCONSIN-CARD-SORTING-TEST (WCST) PERFORMANCE IN NORMAL SUBJECTS- A TWIN STUDY

The aim of this study was to evaluate the WCST, a task linked to the f rontal (prefrontal) cortex, in normal twins to detect an inherited com ponent of frontal lobe function. The WCST scores of 15 monozygotic (MZ ) twin pairs, 9 dizygotic (DZ) twin pairs, and 15 unrelated control pa irs were used to compute genetic estimates. No significant differences were detected between MZ, DZ and control groups intrapair correlation coefficients. No significant heritability estimates different by zero were computed. The frontal lobe function measured by WCST performance in normal twins does not seem to have a high degree of genetic compon ent, and larger samples of twins are required to detect low genetic ef fects. The possible implications of such results about the genetic pre disposition of frontal deficit in schizophrenia have been discussed.