The authors examined cross-cultural applicability of the Schizotypal Personality Questionnaire (SPQ), the Perceptual Aberration Scale (PAS), and the Continuous Performance Test in community samples of Taiwanese adults and adolescents. The authors tested hypotheses that a 3-factor structure of the SPQ (Cognitive-Perceptual, Interpersonal, and Disorganization: A. Raine et al., 1994) exists for both samples and that the Interpersonal factor is associated with poorer attention. The authors replicated the 3-factor model for both samples, and they externally validated the model in adults: The Interpersonal factor and possibly the Disorganization factor were associated with poorer attention, whereas the Cognitive-Perceptual factor was not. The PAS differed from the Cognitive-Perceptual factor in its consistent association with poorer attention in both samples. These have important implications for the scales in the early detection of the schizotypy in various cultures.

Objective: Twin studies are useful for investigating the causes of trait variation between as well as within a population. The goals of the present study were two-fold: First, we aimed to compare the total phenotypic, genetic and environmental variances of height, weight and BMI between Caucasians and East Asians using twins. Secondly, we intended to estimate the extent to which genetic and environmental factors contribute to differences in variability of height, weight and BMI between Caucasians and East Asians. Design: Height and weight data from 3735 Caucasian and 1584 East Asian twin pairs (age: 13-15 years) from Australia, China, Finland, Japan, the Netherlands, South Korea, Taiwan and the United States were used for analyses. Maximum likelihood twin correlations and variance components model-fitting analyses were conducted to fulfill the goals of the present study. Results: The absolute genetic variances for height, weight and BMI were consistently greater in Caucasians than in East Asians with corresponding differences in total variances for all three body measures. In all 80 to 100% of the differences in total variances of height, weight and BMI between the two population groups were associated with genetic differences. Conclusion: Height, weight and BMI were more variable in Caucasian than in East Asian adolescents. Genetic variances for these three body measures were also larger in Caucasians than in East Asians. Variance components model-fitting analyses indicated that genetic factors contributed to the difference in variability of height, weight and BMI between the two population groups. Association studies for these body measures should take account of our findings of differences in genetic variances between the two population groups.

The Continuous Performance Test (CPT) is a widely used measure of sustained attention, which may rely on the efficiency of cognitive inhibition. We examined the relationships of age and sex with CPT performance among 341 randomly selected school children 6-15 years of age. Multiple regression analyses revealed that the hit rate, false alarm rate, and sensitivity of both the undegraded and the degraded CPT were associated with age by a quadratic relationship. The age-development curves for the hit rate and sensitivity were convex, whereas that for the false alarm rate was concave. Sex was associated with the hit rate and sensitivity on the degraded CPT only. Our findings are consistent with the hypothesis that sustained attention develops during the primary school ages. The data reported are essential for identifying children with conditions associated with sustained attention deficit, such as attention-deficit hyperactivity disorder, as well as those at an increased risk for developing schizophrenia.

The aims of this study were to assess developmental trends in performance on the Wisconsin Card Sorting Test (WCST) among 817 randomly selected adolescents aged 13-15 years, and to explore WCST performance factor structure and relationship to schizotypy. The results showed that of the nine WCST indexes, only the Categories Achieved and Failure to Maintain Set scores were associated with age, and only the Learning to Learn scores reached adult levels. Factor analysis of WCST performance scores yielded a three-factor structure. Psychometrically defined schizotypic subjects did not perform significantly worse than control subjects on any WCST indexes. These findings suggest that performance on various WCST indexes might indicate developmental changes at different ages, and deficits in WCST performance might not be sensitive indicators of vulnerability to schizophrenia in adolescence.

This work reports on a study to evaluate the relative contributions of genetic and environmental factors to both competence scales and behavioral/emotional syndromes as assessed by the Child Behavior Checklist (CBCL). A total of 279 pairs of twins and same-sex sib-pairs aged 12-16 years were recruited from 51 junior high schools in Taipei City, Taiwan. Twins' zygosity was determined by a combination of DNA typing and physical similarity. The Mx program was used to estimate parameters for a full model that contains effects from sex-specific additive genes, shared environment, and nonshared environment for the majority of the scales. The shared environment in the full model was replaced with nonadditive genetic factors for some scales when indicated. All girls' competence and behavioral/emotional syndromes exhibited a substantial heritability (h2 > 0.4), except for Social Competence and Withdrawn. For boys, though the heritability was also >0.4 for some scales (Social and School Competence, Thought Problems, Attention Problems, Delinquent Behavior, and Total Behavior Problems), environmental influences, especially shared environment, were predominant for most of the scales (10 out of 15 scales). Genetic factors are important for explaining adolescent behavioral problems, especially for girls, while shared environmental influences cannot be ignored for boys. Gender differences in heritability exist for various CBCL-based competence and behavioral/emotional problems.