Genetic and environmental influences on ratings of manifest anxiety by parents and children.

Parental reports and children's self-reports of manifest anxiety were obtained from a community-based sample of twin pairs on two occasions approximately 19 months apart, using the Revised Child Manifest Anxiety Scale (Reynolds & Richmond, 1978). In prior cross-sectional studies, a low degree of agreement between parent and child assessments of anxiety was found. Furthermore, parental reports were found to reflect a higher heritability than children's self-reports (Eaves et al., 1997; Thapar & McGuffin, 1995). The index of temporal stability was moderate for all informants (circa r = .5 to r = .6). To test whether the components contributing to the temporal stability differed between the informants, structural equation models were fitted to the data using the program, Mx: Statistical Modeling (Neale, 1995). The results showed substantial differences in genetic effects according to both gender and informant. For children's self-reports, temporal stability was largely a function of environmental effects, with genetic effects contributing a modest 20%, whereas for parental reports, temporal stability was largely a function of genetic effects. The heritability was higher for parental reports than for boys' self-reports and the genetic covariance between parents and their sons was near zero, indicating that they were reporting on quite different aspects of anxiety. However, for girls, heritability for maternal reports was lower than for self-reports, and the genetic covariance between mother and daughter was about the same as that between mothers and fathers, meaning that they were assessing the same genetically influenced aspect of anxiety. These results highlight the need to focus on gender differences.