Suchergebnisse

AbstractWe examined whether effortful control (EC), a temperament proposed by Rothbart and Bates (1998), has genetically coherent structure. A self- report measure of EC was administered to 450 Japanese twins (151 males and 299 females, ages 17 to 32 years) including 152 monozygotic and 73 dizygotic pairs. Univariate genetic analysis revealed that AE model fit best for the total EC as well as its subscales. The heritability estimate for total EC was 49%, and the estimates for subscales ranged between 32% and 45%. Multivariate genetic analysis revealed that the subscales of EC were genetically correlated to a high degree and environmentally correlated to a moderate degree. These results suggest that EC has substantial genetic basis and genetically coherent structure, supporting the validity of the construct. The implications to molecular genetic study and study of psychopathology were discussed.

We report the first community epidemiological study of taijin kyofusho in Japan. A total of 132 inhabitants in a small community in the city of Kofu, Japan, was interviewed by trained interviewers using a semistructured interview, and completed self-report questionnaires. Of these respondents, nine (6.8%) reported ' taijin kyofu' symptoms, eight of whom reported having specific concerns about strong body odor although the ' taijin kyofu' symptoms were not serious enough to meet the criteria of a mental disorder. Although taijin kyofusho has traditionally been viewed as a disorder of young males, our cases were older and predominantly female. Although this sample was small and drawn from only one community, and we had no control group, our findings seem to support the view that some psychiatric symptoms are influenced by socio-cultural factors and that the symptoms of taijin kyofu are likely to be found in the general population of Japan.

To investigate the prevalence rates and characteristics of poorly explained or unexplained somatic symptoms in the general population of Japan, questionnaires were administered to 132 people aged 18 years or older in a small community in the city of Kofu. The participants were then interviewed by trained interviewers using a semi-structured interview schedule. Of the 132 participants in our study, 55 (41%) reported somatic symptoms. Of these 55, nine (16%) were diagnosed with a specific DSM-IV somatoform disorder. Multiple regression analyses revealed that the number of poorly explained symptoms among women was related to the respondent's score on Neuroticism. These data suggest that poorly explained or unexplained somatic symptoms are related to personality characteristics. Moreover, our analysis also revealed a gender difference in the pattern of these relationships. None of the respondents who reported medically unexplained somatic symptoms had sought psychiatric care.

Background: As the suicide rate in Japan has remained high since 1998, various suicide prevention measures have been implemented in Japanese local communities. Aims: To report our findings on the effect of a psychoeducational video as a suicide prevention measure in a Japanese rural town. Methods: Questionnaires were randomly mailed to 2,000 residents aged between 30 and 79 years. Within 4 weeks, volunteers in the town visited the residents individually and collected the questionnaires. The variables reported in this study are demographics, awareness of suicide prevention measures available in the town, whether the residents watched the video, help-seeking from advisers regarding suicidal ideation and financial problems and attitudes towards suicide. Results: We analysed data collected from 1,118 people who reported their demographics (i.e. sex, age, and job) and whether they had watched the video. By conducting a series of logistic regression and multiple regression analyses and controlling for demographic variables, we found that watching the video had substantial psychoeducational effects. Conclusion: Despite conducting a cross-sectional study, our new suicide prevention measures were considered effective for psychoeducation. However, further studies using a longitudinal design are needed.

AbstractAmultidisciplinary collaborative study examining cognition in a large sample of twins is outlined. A common experimental protocol and design is used in The Netherlands, Australia and Japan to measure cognitive ability using traditional IQ measures (i.e., psychometric IQ), processing speed (e.g., reaction time [RT] and inspection time [IT]), and working memory (e.g., spatial span, delayed response [DR] performance). The main aim is to investigate the genetic covariation among these cognitive phenotypes in order to use the correlated biological markers in future linkage and association analyses to detect quantitativetrait loci (QTLs). We outline the study and methodology, and report results from our preliminary analyses that examines the heritability of processing speed and working memory indices, and their phenotypic correlation with IQ. Heritability of Full Scale IQ was 87% in the Netherlands, 83% in Australia, and 71% in Japan. Heritability estimates for processing speed and working memory indices ranged from 33–64%. Associations of IQ with RT and IT (−0.28 to −0.36) replicated previous findings with those of higher cognitive ability showing faster speed of processing. Similarly, significant correlations were indicated between IQ and the spatial span working memory task (storage [0.31], executive processing [0.37]) and the DR working memory task (0.25), with those of higher cognitive ability showing better memory performance. These analyses establish the heritability of the processing speed and working memory measures to be used in our collaborative twin study of cognition, and support the findings that individual differences in processing speed and working memory may underlie individual differences in psychometric IQ.

The Keio Twin Research Center has conducted two longitudinal twin cohort projects and has collected three independent and anonymous twin data sets for studies of phenotypes related to psychological, socio-economic, and mental health factors. The Keio Twin Study has examined adolescent and adult cohorts, with a total of over 2,400 pairs of twins and their parents. DNA samples are available for approximately 600 of these twin pairs. The Tokyo Twin Cohort Project has followed a total of 1,600 twin pairs from infancy to early childhood. The large-scale cross-sectional twin study (CROSS) has collected data from over 4,000 twin pairs, from 3 to 26 years of age, and from two high school twin cohorts containing a total of 1,000 pairs of twins. These data sets of anonymous twin studies have mainly targeted academic performance, attitude, and social environment. The present article introduces the research designs and major findings of our center, such as genetic structures of cognitive abilities, personality traits, and academic performances, developmental effects of genes and environment on attitude, socio-cognitive ability and parenting, genes x environment interaction on attitude and conduct problem, and statistical methodological challenges and so on. We discuss the challenges in conducting twin research in Japan.